stargeek - 7:59 pm on Jun 27, 2006 (gmt 0)

google has said time and again that nothing another webmaster does can hurt your rankings. so if you believe the official google line, then no, IBLs cannot hurt your ranking.

anctedotally however, i've seen countless examples of site where large number of low quality and unrelated purchased links have seemed to at least raise a red flag about a site. and google bowling is considered to be a functioning way to knock a competitor's site out of the serps.

so my advice is that if you're positive there's nothing else shady going on with the site, then no you'll probably be ok with a few sketchy links, especially if they are outweighed by quality IBLs.
on the other hand if the site commits flagrant violations of seo guidelines you may want to be more careful as far as the pacing and volume of questionable IBLs.