JonathanD - to be clear, the signature links are nofollows, but the general profile website link is one that is able to be seen by search engines, right?

Even though signature links are usually 'nofollow' they still get you traffic. Just not page rank.

But if you are in a relevant and high page ranking forum or ezine site blah.. and you make sure to sprinkle your keywords in posts here and there, your posts can have excellent page rank and therefore traffic too via your sig, so they're still good just a little more indirect.

This are some of the things google bot looks from a website. Hope it will be of a help
- google bot crawls your page if your site is loading fast ( so if you page is correctly build, using standards etc )
- Title of the page can be anything, but it should be a nice keyword you are after
- checks what references the page has, not the number of backlinks
- google bot loves info because google bot searches for keywords, and if you have content , you have keywords
- flash site is made for visitors for example but its not that great for SE.

Forget about PR - it is overrated... are you in the blog directories? try http://blogs.botw.org/

and do a search for more... also have you submitted to the blog aggregators like feedster etc?