One of the reasons WordPress has become the biggest publishing platform on the web is because it’s easy to extend the basic features with plugins.

That makes it simple to add things like social sharing links or image galleries or even to transform WordPress into an online store, discussion forum, reviews site, niche social network, video / image sharing site, classified ads site. The list of what you can do is practically endless.

Rather publish an overwhelming list of plugins, I’ve stuck to listing the best plugins for the most common tasks as well as make suggestions on how to use them effectively.

Quick Links to What’s On The List:

Social Plugins
Newsletter & Mailing Lists
User Reviews
Contact & Order Forms
Image Galleries
Linking Plugins
SEO
Google Analytics
Site Speed
Security & Backups
Mobile Plugins

WordPress Social Plugins

What good is all that great content you’re producing without promotion? One of the best forms of advertising is word of mouse – link shares, Twitter mentions, Facebook likes and +1s by people who appreciate your content.

Remember, the easier you make sharing, the more users will do it.

To encourage link sharing try Add This, probably the easiest way to show a classy row of buttons for all the main social networks. There’s also ShareThis which is similar but has both horizontal or vertical bars and has more choice of styles. This is the kind of social bar you see on sites like Mashable.

Both services allow you to create an analytics account so you can track exactly how and where your content is being shared.

Best Placement
Web designers are in the habit of putting sharing links at the top of the page but that’s not always the best place for them.

Sharing links usually work better at the end of your content. Readers who’ve made it that far are either your mother or very engaged with your content.

Either way, they’re more likely to share – especially if there’s a shiny tweet button in front of them.

Don’t go overboard with the buttons. You probably only want to show buttons for Facebook, Twitter, Google+ and Pinterest (especially if your site is image, video or product focused) and a niche social network site if that makes sense for your site. Don’t forget to use an email button – many users still love to share stuff by email.

To create icons that link to your social network profile pages, take a look at the Social Media Widget which has a number of icon styles and is completely customizable in WordPress Admin.

Google Circles is becoming more important, especially now the search results algorithm includes AuthorRank. There’s a simple plugin called GoogleCards that shows a link to your Google+ profile and lets users add you to their Circles.

Tumblr & WordPress
If you post mainly in WordPress but want a way to publish simultaneously to your Tumblr account, try Tumble which adds a one-click Post to Tumblr option for your posts, image and other media files. Or, for a more complete Tumblr experience take a look at this Tumblr plugin which also allows you to delete and reblog without leaving WordPress Admin.

You Tube
While there are a few YouTube plugins around Smart YouTube is one of the the best options. It’s recently been updated and now supports a number of other social video sites including Vimeo, Metacafe, Liveleak and Facebook. It looks great on the iPhone and iPad too.

Newsletters & Mailing Lists

There are quite a few newsletter and mailing list options for WordPress but watch out. Many of them are intended to send the emails from your web server and there are fewer and fewer shared / grid server web hosts that will let you do that. It’s also too easy for your mailings to get tagged as spam and to get you into hot water with your web hosting company.

Better to stick with a hosted newsletter solution. Three worth recommending that have a WordPress plugin are MailChimp, AWeber and FeedBurner.

Mail Chimp is the easiest to use and your first 2000 subscribers are free. But bear in mind the Mail Chimp content policy doesn’t allow affiliate marketers, “make money from home” style mailings or certain financial sites like credit repair and mortgages . That makes it great for small businesses and organizations to keep in touch with their users but not suitable if you’re working with affiliate marketing.

Instead, most professional web marketers choose AWeber for their mailing lists and newsletters. It comes with the best set of features in the industry and at a lower price than many other systems.

FeedBurner isn’t a mailing list service in the true sense, but as well as handling your RSS feed, users can opt to be sent your new posts by email.

While there’s not much you can do in terms of customizing the email output, it’s easy to incorporate AdSense for Feeds to monetize your content.

There’s no plugin I know of that seamlessly integrates everything including the signup form, but FD FeedBurner redirects all blogs feeds to your FeedBurner account, while FeedBurner Circulation displays your subscriber count, which you’ll find encourages new users to subscribe if you have a fairly large readership number to display.

Review Sites

Trying to set up a reviews site in WordPress used to be a pain. Recently a premium plugin, WP Review Engine, has simplified the process to the point where you should be able to get a full review site online in half an hour or so. Check out the live demo.

I’ve yet to find a free review plugin to recommend.

Contact & Order Forms

For a simple contact form try Fast Secure Contact Form. You design your contact form and then use a shortcode to place the form within pages. The great advantage of this over templates is you can reuse the same form in several places.

Another good freebie is Contact Form 7. It’s similar to Fast Secure Contact Form but it’s a good choice if you need your form in a language other than English.

If you need something more professional for your business take a look at Gravity Forms. Using a smart form builder it’s easy to construct anything from a simple contact form with auto-responder through to complex order forms with conditional sections that display depending on the customer’s previous responses. That’s useful for an order form that updates prices as users select or deselect items, for example, or for questionnaires and surveys.

Gravity Forms have a number of add-ons allowing you to use your form with AWeber, MailChimp, Campaign Monitor, PayPal, Authorize.net and Twilio.

Image Galleries

Best of the bunch for sites that use a lot of images is arguably NextGEN which has every option you could possibly imagine including a Flash slideshow, ability to add image effects, automatic thumbnails, lightbox gallery and sidebar widgets.

NextGEN is fairly advanced and might be overkill if you just want to show the occasional gallery. For that you might want to look at Lightbox Gallery which turns the standard WordPress gallery shortcode into a lightbox gallery where the main content is dimmed and the images are displayed on top.

Also worth a mention is Flickr Photo Album for showing Flickr albums and
Photosmash Galleries which is excellent if you want users to be able to contribute photos.

Linking & Affiliate Plugins

For a simple plugin to make internal linking easier take a look at Term Descriptions. Suppose you’ve just written a post about WordPress premium themes and you want to create links to it from older posts. Instead of manually adding the links to your old (and future) posts, you can setup a list of terms and links and this plugin will add the links for you.

You can specify multiple terms for the same link, set a maximum number of links per page and exclude certain posts, pages or areas of content from automatic link generation.

If you’re looking for a way to track outgoing links (like affiliate links) Pretty Link Pro is a smart choice. One of the standard tools used in affiliate marketing, it has practically every redirect and tracking feature you could want.

It’ll also allow you to split-test combinations of link text wording and urls to help you quickly see which is the best combination. Because it can automatically generate urls you can use it as a url shortening service and QR code generator. Checkout the full feature list here.

WordPress SEO Plugins

One of the reasons I recommend WordPress is that it’s so easy to tweak for search engine optimization. Two plugins make this crucial but tricky task easier:

WordPress SEO can automatically optimize your page titles and content and generate search engine-friendly XML sitemaps. There are also plenty of options for advanced users to work with. Fully compatible with Genesis and Woo Themes for WordPress.

All in One SEO Pack has a similar set of features along with support for Custom Post Types and WP e-Commerce sites. Advanced users and web developers can use it to fine tune navigational links and canonical urls. It also has its own API so that it can be extended by other plugins and themes.

There are a few paid / premium SEO plugins for WordPress but none are an improvement on either of the free options above.

Also worth mentioning is Google XML Sitemaps which automatically generates an XML sitemap for your entire website and submits each new version to Google, Yahoo and Bing. These mean that these search engines will be notified the moment you add a post so your new content gets indexed quicker.

Google Analytics

Google Analytics has quickly become the industry standard for measuring audience visits and interaction with websites. To integrate the stats program with WordPress try Google Analyticator which is a simple way to put the tracking code on your site so you can start measuring visits.

More advanced users might prefer Google Analytics for WordPress. This really is a great plugin, giving users access to stats that would be difficult – if not impossible – to set up with Google Analytics alone. If you need to know things like whether older posts are still drawing in lots of long tail search engine traffic or want to follow the navigation paths of logged-in users, this is the plugin for you.

Site Speed

Closely related to SEO these days is the responsiveness of your site. The faster it loads, the better. The busier your site is the faster it’s likely to load if you install a plugin like Total Cache or Super Cache.

Both of these work in similar ways – they temporarily store, or cache, the content of your website as visitors browse pages so that subsequent visitors don’t have to wait while the same information is called all over again from the WordPress database.

For me, Total Cache just has the edge over Super Cache but if you’re not a technical type you’ll probably find Super Cache easier to set up.

Compressing your images will make them load faster, so if you have an image-heavy site even a small saving in file size can have a substantial effect on site speed. Fortunately, you don’t have to do the image compression manually. Just install WP Smush.it and you’re done. There’s nothing to configure, no extra steps when uploading images and you can compress the images you’ve already uploaded.

Security & Backups

After working hard on your website content you definitely don’t want to run the risk of losing that content if something should go wrong.

That’s why I install WP-DBManager on every site I set up to make frequent automatic backups. You can even have those backups emailed to you as well as saved on your web server.

Bear in mind that WP-DBManager only makes copies of your database, so only posts will be saved – not your design files, images and so on. For a backup system that protects everything take a look at BackupBuddy which can backup and restore your entire WordPress installation. It’s great not just for peace of mind but also if you need to change web hosting companies and don’t want to risk losing something or have to hire a developer to do it for you.

Mobile Plugins

Having a mobile-friendly version of your site is increasingly important. WordPress Mobile Pack installs a number of free mobile themes to get you started as well as an automatic switching system to make sure users viewing on phones and tablets see your mobile-optimized site.

Want to post and edit on the go? Check out the official WordPress suite of mobile apps for the iPhone and iPad, Android phones and tablets, BlackBerry, Windows Phones and more.

Other Useful Plugins

Turn your site into a WiKi style site like Wikipedia with WordPress Wiki.

Dead links drive users crazy and are bad for SEO. Broken Link Checker helps you track them down – a major time saver if you have a large site.