Search Engine Blacklist is a pretty basic idea. Block the domains that you view as spam from your Google Search results. Then, upon your next Google search, you'll never see that domain ever again. Simple concept. Pretty sweet implementation, right in your Chrome browser.
Personally, we have a vendetta against Experts Exchange for their layout and head games they'd play with people looking for answers. And although we are certainly not advocates for any illegal activity here, this also helps with finding software, music, and torrents by blocking those that constantly show up as spam. It'd be nice if there was an option to aggregates everyone's blacklists so we don't have to manually type each one in, but perhaps that'll be something to look forward to in the future.
You can grab the Chrome extension over here.