Over a one-week period I added more than dozen links though BH methods ( I could have added more but I did a dry run of 20+ links to see if I would get a boost. I did not want a penalty for adding too many at once) , including some EDU links. These were not spammed guestbook links. The links were indexed I know. I varied anchor text and targeted five specific pages and keywords. Also used the raw url as the anchor as well to make it look more natural. The domain is pretty old and established. Verdict: zero change for any of the targeted keywords and no bump in search traffic. totally useless . One of the pages fell in rankings (from page 9 to NA) . The only possible difference is it seems like Google indexes new pages faster and caches the index page more frequently. None of the pages saw any ranking improvement. Don't pay for links..not worth it.