I'm thinking it would be very simple for Google to go through and subscribe to these various services or create fake forum profiles requesting "free links," then run an analysis on all the links pointing to their dummy site and put a block on the link juice making them worthless. If so it seems like any popular link building service should be avoided. Makes more sense to build your own private networks and become less reliant on outside links. I've also been very careful lately about URL and Anchor normalization now and I have seen no recent impact in SERP, where there is any, it's very minimal. I'm convinced normalization, layering and variety are KEY right now. Anyhow, I was just curious, maybe someone has a solid answer for me. If I worked at Google, that's probably what I would do. lol. Thanks.