Are Squidoo lenses good marketing vehicles for books?

Author Dee Power posted about her efforts with Squidoo lenses, which serve as marketing vehicles for her books. You can see Dee's lenses here:

Dog Friendly Vacations
How to Get a Book Published

Dee was especially pleased that she managed to get one of her lenses into the top 100. Unfortunately, this didn't generate many book sales:

There was one sale from How to Get a Book Published and none from Dog Friendly Vacations. It doesn't seem that a Squidoo lens is effective in generating sales, at least not for me.

Coincidentally, I've seen anecdotal reports about Google penalizing Squidoo lenses in search rankings. According to the reports, Google downgraded Squidoo pages because of too many spam lenses. The SEO crowd even has a name for it: The Squidoo Slap.

Squidoo is an easy way for people to aggregate good links about a specific topic. But like any good tool, it's attracted spammers, especially blog comment spammers.

I'm not an expert on search engine optimization, but I think all this just reinforces one basic idea that authors should remember about online marketing: If you're going to invest a lot of time creating content on the Internet, keep your best stuff on your own domain. It's fine to have a presence on these social-networking sites, but keep your crown jewels at home.