I thought it would be best to start off with something so basic – so simple – yet totally missed by so many. This should be taped to the monitor of every webpreneur around the world so they see it on a daily basis. An idea should never get beyond the simple ‘idea’ phase without making sure that it passes this ‘test.’ Ready? Commit this to memory:
See a Need, Fill a Need.
See, I told you it was painfully simple. But trust me, if you follow this mantra, you will greatly increase your chances of success. If you spend any time on message boards that deal with starting forums or making money online (this concept should be applied to ANY business – online or off), you probably see groaning new admins complaining about their dead message boards that have been ghost towns since their fairly recent launch. “Why aren’t people joining my board? I spent all this money on a cool skin and vBSEO, yet I can’t get people to join and start talking. What do I do!?!”
My first question would be, “What keyword research did you do? And what did that yell you?” Often, they did none. They simply wanted to start a board on that topic. If you build it, they will come, right? Well, my friend, that just isn’t good enough in 2006. With around 50 million registered dot coms, you need a LOT more than just an interest in a topic to do well.
If people aren’t coming to your board (provided you have some rankings – which aren’t hard to get in MSN or even Yahoo!), or if they are coming and not staying, you probably are trying to fill a need that isn’t there. I hate to be the bearer of bad news, but it’s fairly black and white.
Okay, so let’s say you haven’t started your board yet – how do you make sure you are filling a need? It’s actually a fairly simple process. That, however, deserves its own post since for me, that part is lots of fun. 
You make a strong point Laura, and one that is overlooked by many.