Tim Farley is a skeptic and the creator of the What's the Harm? website, where he details the harm in believing in antiscience. He also writes a blog called Skeptical Software Tools, and he had a very interesting post recently about the Long Tail of blogging skeptically.
The Long Tail is the idea that in any population, a few objects get the lion's share of the influence. For example, take something you judge by popularity -- TV shows, books, blogs -- and you'll see a very few are hugely popular and enjoy a lot of traffic, but the vast majority don't get nearly that much traffic. However, taken collectively, that long tail distribution of less-popular things might have the same traffic in total as the most popular things.
An example: PZ Myers has the most popular science blog on the planet. Mine gets less traffic than his, and a handful of other science blogs may get what's considered to be a lot of traffic. Then there are the thirty bazillion remaining science blogs which get less traffic individually... but if you add up all their traffic, they probably get as much as PZ and me and the other "top" blogs combined as well.
I get email sometimes with someone asking me how they can write a blog that's really popular. I tell them, first build a time machine... because you'll need to start ten years ago.
Tim's point in his Long Tail post is similar. You'll probably never be able to start a skeptical or science blog that'll get huge (you might, it's just unlikely at this point). But that's not to say you can't make an impact. In fact, there's a real niche -- and a need -- for targeted skepticism. Instead of tackling a broad range of things, find one thing that ticks you off and have at it. Jenny McCarthy, Robert F. Kennedy Jr, James van Praagh, Kevin Trudeau-- these are all people who need debunking, and a blog dedicated to tearing apart their antiscience can still generate traffic, and get good Google search engine results.
Look at Stop Sylvia Browne, a blog by Robert Lancaster. By staying focused and targeted, it swiftly climbed up on Google and is now one of the top searches on her name. Same thing with Stop Jenny McCarthy. Take on one of these people, or a specific flavor of antiscience -- there's plenty to choose from, sadly -- and you can make a real difference.
I encourage you to try. If there's some particular brand of nonsense that sticks in your craw (and if you read my blog, I'll bet there is), start writing about it! And don't be afraid to ask for links from bigger blogs. The next thing you know, there might be one less thing to write about, and the world will be a better place.