It's either well a well planned out first page or it just happend that way but if you notice the keywords. Electro-tech online: "Electronic Circuits Projects diagrams Free"
Everyone one of those is going to be top on the list of keywords that people look for, and because of the overall traffic the site gets it ranks high on Google, so that's a big part of it. Google also seems to process all the forum traffic here too, so people looking for specific things ususally find it on Google. When someone asks a tough question here I tend to Google it see what pops up on the first few links, if it's a really rare question or what not the only link I'll find is the google link to the thread that posted the question I'm trying to find an answer for =O So either because electromaster has it setup that way or Google just likes us they keep a real close eye on the forums.