Three interesting points from this video
1) Indicating what some have been saying for a long time. Dofollow blogs actually degrades a pages reputation in the eyes of Google. So getting a link from them is not the same as getting a link from a high PR page that doesn't allow wide open commenting.
2) its senseless arguing about the term Dofollow. some people get bent out of shape about using the term yada yada yada. All it means is that if a search engine encounters it it will follow it. Either way when Google uses the term themselves then its evidence of how mainline the term is in SEO.
3) Getting dofollow links back to your site won't hurt you but given that Google warned bloggers in November 2009 and are back again in February 2010 expect alot more sites to go nofollow. Really it now makes no sense for ANY reputable sites to allow unmoderated dofollow commenting because it does nothing for them and now they will begin to realize that it actually hurts their site.
The take away for people building links?
If your goals are short term and you spend a lot of time doing blog commenting just be prepared for those links to disappear. Its not a good long term strategy. Theres no reason for the web masters to leave them there now with Google actively telling site owners theya re degrading their sites reputation because of it.
For people who own blogs that they want to rank?
Obvious. moderate your comments or make them all nofollow. Most will end up making them nofollow since with the commenting bots around you can get hundreds of nonsense posts to moderate every week or month.
I know of course some people won't like this post but those be the facts.