Think about what a search engine and social network might look like if built as a combined site from the ground up. Throw in a little Pinterest and that's what you get with So.cl. Lili Cheng, general manager of Fuse Labs, the Microsoft division that built so.cl, will deliver the keynote on April 25, Day 3 of the Search Insider Summit in Captiva, Fla. So.cl attempts to turn social networking inside out, where the Web become accessible from within the site and content shared with connections. Bianca Bosker at Huffington Post tells us a little bit about the Invitation-only site, which debuted on three college campuses -- New York University, Syracuse University, and University of Washington. The site has grown to more than 25,000 users in the past two months, but expect many more when it opens to the public.