I have been thinking about these.
The great thing about Squidoo and Hubpages is that the domain has lots of authorty from the get-go. What you can do, is you can use these as micro-niche sites. So if there is a topic that has a good adsense return, then instead of having to build a 20+ page site to buffer again Google, you could instead set up a page on Squidoo. Unlike your website, you don't have to constantly add new content to it to keep it up there and secure against rankings. Your squidoo/hubpage will rank quickly and need less backlinking. You can also take advantage of internal traffic.
... on the other hand, adsense doesn't usually earn you much money; and you
can't sell you hubpage/squidoo page. Like, if you get a website making $20 a month, you can sell that website for $200. But you can never sell your squidoo/hubpage. So you're only ever going to get your adsense money; you can never cash out.
That said, I'm actually considering experimenting with Squidoo myself. The ease of ranking means that it could be the way forward for MNS's and I've got a great niche to do it in

but you have no control of the theme so CTR could suck