This is a huge question. Different tools find different backlinks. For example, checking my Free Web Graphics -- How to Get Them (Legally!) lens on SquidUtils' Backlink Checker, I get this:
This URL has 1000+ links from 6 domains.
- angelfire.com 1
- annbrundigestudio.com 20
- digg.com 1
- mythphile.com 25
- squidu.com 952
- squidutils.com 1
(Once again demonstrating the limitations of social media for SEO, since the links from StumbleUpon, Del.ici.ous. Tagfoot and others don't show up.)
1000+ backlinks is pretty good, right? Well, yeah, assuming (a) all search engines see the same backlinks as Yahoo Site Explorer (the database SquidUtils uses), and (b) all search engines count those links as relevant. But of course, they don't.
