Rollyo and other stuff

So, I played around a bit with LinkedIn, Library Thing and Rollyo. I actually think my favorite was rollyo. I like the idea of customizable search engines. In a sense, it's creating a pathfinder of sorts for the internet on specific topics. I think it could be quite useful in library applications. I was not as impressed with LinkedIn, the concept is good, social networking for the working professional. But I'm not sure that I personally would use it all that much and when I tried to find colleagues from a past job, their search function did not work very well. Library Thing is a great concept and I've explored it in the past. It seems to expanding rapidly into many venues and applications, but I am using another site to keep track of books I've read.