So I did the keyword research for the 30 Day Challenge, just like Ed described; I checked the competing pages for my KW, and found they should be easy to beat; and I got my web site up and running. Only then did I venture forth into the "aisle" I'd chosen in the Internet Marketplace -- to find I'd probably set myself up for disaster.
Everyone in that part of the marketplace is there because they're selling something. They don't talk about it, they sure don't seem to have any "community," and they don't really care about the other people there to do the same thing. They're just selling. There are no forums on my niche; there are very few places to leave comments; and it seems the people there are simply searching for what they want to buy. My KW research said that there were 161 searches a day and (651/6200, depending on the day I did the research) competing sites; but my Digg is gone from the search results now, and at most it got me 50 visitors, and nobody bought a thing. I'm going to have to work REALLY hard to make this a going concern; and it still might not return anything.
My Point: Do your Market Research. No, really. Don't just look at the results your Keyword Research tool gives you; as wonderful as it is for us 30DCers to have all that information in one place, it only tells half the story. The other half can only be gained by walking that aisle in the Internet Marketplace -- seeing if the people along it just hawk their wares or if they have formed a community around their common interest. And I can only say, for myself, that the next time I take that walk and all I see are sales listings, with no blog entries, forums, or "gateway sites" (sites that serve as a place that people into this market can go and share stuff with each other), I'm going to have to step back and think. REALLY hard. I can try to become the gateway site for my niche, but with people being this non-talkative, somehow I don't think so. I'm still going to work at it, though; and in the meantime, I thought I'd pass this on as yet another thing to take into consideration (as if we need another one!

) My IMU keeps harping on "research, Research, RESEARCH!" -- I'm beginning to understand what they mean.
Just trying to be helpful (and make sure I don't forget myself!)