I think it depends, those do-follow comments really give a initial boost to your sites but the vast majority of those sites the comment section is not Auto Approve and the guy who is selling you this service for sure is not going to comment on all the sites, he will use some program.

Based on that maybe you would have a much better result doing it by yourself, really comment on the blog posts, adding value to the owner of the blog and, by consequence, getting a high approval rate of your comments/links.

Never had used before their toolbar but its just great, i was using the SEO Site Tools but just turned that off now

Actually I really liked the "content registry" idea.

An library of content where you could register what you have created and, optional, a link to where you want to be considered the main source.

At least it would be 10x more usefull than the google knol idea..

I think the Parasite Hosting is when you put some content on a domain that have great page rank, in this case creating a page on squidoo (wich have PR 7) with some keyword that he wants to rank and then put a link in this page to any website he wants to.

Im kinda curious about if this is still working, those sites were not penalized with the panda update aswell? If not, it would work but I can say that this is something that would be in the blackhat or, at best, grayhat area.