Looks to be all old linkstoyou.com links. I don't think its a link farm. Of course, I just looked through backward links on alta.
How's the search going? I tried that once but never really found anything worth the effort in terms of linkpop. However, I had a script going that took about a second per domain and would crash occassionally in the middle of a list - so I didn't check but a few thousand. Let us know if it is a fruitful endeavor.