There's already a tool--more like a webring with integrated browser add-on than a wiki--called StumbleUpon. It works with Firefox. I don't know if it works with another browser. If you post your email address I'll send you an invitation and the URL if I can find it. Categories include electrical engineering, electronics parts, physics, and semiconductors. You can "stumble" within a category, but you cannot "search" within a category. For that, use a search engine like startpage.com or dogpile.com.