When linking with other sites, I'm seeing that almost every site on the planet has a catagory that is related to my field. For example, I'm looking for back links to link up with my pet sites, and am finding sites devoted to "cabinet making" and other totally irrelevant sites, with pet catagories in their own directories. Should I be linking to these sites, or only linking to pure pet sites? Thanks.
A link is a link. If you can get a link on a cabinent making site with a directory that has a pets category then go for it. The link will not hurt one bit but dont expect any traffic from it. Linking on other pet sets is ideal though because you will get the added bonus of targeted traffic. Just remember that Google doesnt penalize you for any link out there since you the webmaster has no control over who links to you. So just remember my saying "a link is a link" But dont join automated linking programs because they can be detected and penalized (reported by numerous people).
Aaron, I respectfully disagree that a "link is a link" because some links are just so useless that they won't help you with traffic or rankings, but will just suck up your time to source and submit to. I wouldn't bother with anything that wasn't relevant.
Also there's the potential that if it's a link on a "bad" page the search engines might penaltize you for it. Rare, but it happens.