I was checking the backlinks in Google for one of my Hubpages, and found that they counted my Hubpage Profile page as a backlink. It made me pause to think. How was this profile page sufficient to propel my hubpages up the SERPS?
The answer is through the forum. Every time you post in the forum, you leave a link behind to your hubpage profile. The more links, the more powerful your Hubpage profile becomes. The same thing applies to Squidoo - they too have a forum (called Squidu), and again, when you post on there, there is a link in the left to your profile. Squidu also allow signatures, so you can build additional backlinks to individual sites (not confined to Squidoo lenses).
It seems to me that both Hubpages and Squidoo are designed to reward people who interact with the community. Having lots of fans gives you the same benefit - you end up with a lot of other profiles linking to yours, giving you link juice.
On both sites you can also add blurb and links to your profile page to emphasise certain keywords linking to certain pages/blogs/lenses.
It's tempting to ignore the social aspects of Hubpages and Squidoo. But because of the structure of the sites, they genuinely deliver benefits to the pages/lenses that you write if your are socially active within the communities - because your profile starts to gain authority in it's own right and then starts to push any pages listed in your profile up the SERPS.