StumbleUpon is my favorite social marker.

i think squidoo is good if you are an affiliate marketer. if you have favroite books that and like to write great how to articles, you can make an extra income with their site. as far as generate long term business i don't think it will do unless you are an author selling a book.

Best I've seen so far from squidoo is a PR1 on a page that's not their own.

Not that a PR1 isn't important, it would take a PR0 right off the bottom.

A more useful link or page would be a post on a forum that allows your URL in the signature. It has to be a popular enough forum to have solid pages cached with responses to them. There are plenty.