they are probably doing simple stuff like checking the type of words they used. Like if twit has "xoxoxo" then its a female or they check the user's friends and look for references to the user in their twits. i.e. "vijayr posted that [he] created a new thread on hackernews"
hmm. that much isn't difficult to do - I checked out the site, didn't find a single mistake in 7-8 attempts of searching. Does this mean, that they also determine businesses/organizations and drop them from their list?
