This is a cool way to get high profile sites to link to you. Here is what you do....set up as many "profile" pages as you can with all the popular sites....such as Yahoo, Ebay, Aol, etc. For example, your yahoo page would be http://profiles.yahoo.com/[username] Nearly all these pages allow you to place your own links on them. Once you've set them all up, then submit them to Google. I just checked and my Yahoo Profile page has a PR7! Check it and lets get opinions.
this sort of thing does work when done correctly on the right profiles, but the majority of them (like yahoo) won't get you too far. things like DMOZ, especially if you're listed as an editor in multiple places, can easily have a great PR, and you're allowed to plug all the sites you own there. there are other examples as well. deviantart sites tend to do somewhat well. some livejournal pages do too.
My yahoo profile pages are pr0. I never thought of submitting those pages to the search engines though....interesting idea.
Profiles may rank high, but I don't believe that help your site rank high as well Forum signatures are more helpful for achieving such purpose.
what are you basing that on? from all of my experience, forum sig links are just about useless for helping things rank. they may help for direct traffic, but that's really about it. that makes sense as well: look at how many links there are on an average forum page. not to mention that automated forum spam is pretty much the new blog spam; pretty sure google's aware of it.
I've got a few rather large forums where I have over 100 posts, some with much more than that. changing the anchor text did virtually nothing to change the rankings compared to say, a miniscule amount of weight from the coop.