Spool is one of the those startup ideas that seems like such a good idea until you realize their business model is about to go down the pan. Here’s a look at why, so you don’t make the same mistake.

There are quite a few apps around designed to allow access web content when you’re offline. Instapaper is probably the best-known and certainly one of the earliest providers of this type of service, letting users to save long web pages to read later on their PC / Mac, iPhone, iPad or Kindle.

Now a new app called Spool is doing the same thing for videos – reformatting and saving them so they can be accessed on your mobile device later. Even when you’re offline.

So far, so good. But…

Who hasn’t been stuck somewhere without an internet connection and wished they could watch a video or two as a time-killer? Sounds like a winning idea for a business.

Except the very problem Spool is solving is about to disappear, leaving it with no business model.

We are now surrounded by Wi-Fi, much of it free. Coffee shops, restaurants and stores give it to us in exchange for our business and you can be sure that trend will continue.

The number of places that are truly offline is decreasing all the time. That means there are fewer and fewer reasons to use Spool and other apps whose sole business model is offering offline web access.

Even the last two places where getting an internet connection has traditionally been impossible – in the air and on underground rail systems – are about to go online. Airlines like Delta and Southwest are starting to offer in-flight internet and the London Underground subway system installed Wi-Fi in the London tube system in time for the Olympics.

What you can learn from this

Instapaper launched a long time ago – when offering offline access really was a useful thing and long before anyone could predict the widespread coverage of Wi-Fi.

But Spool is a recent startup. They have no reason not to understand that people will spend a lot less time offline in the future, diminishing their customer base. The occasional offline period is easily covered by the offline storage features of HTML 5, already being used by sites like You Tube to fill in where needed.

The future isn’t always easy to predict – but sometimes it is.

Before committing yourself to an app or web service that solves a technology problem, do some research and make sure there’s not a solution on the horizon – even if it seems a long way off right now. If there is, you probably need a different idea.

Update: The first draft of this post was originally written on the morning of July 14th. Turns out that later that same day Spool closed down.