No Follow, Do Follow, Lets All Follow Matt Cutts
The SEO industry is forever changing and forever increasing in demand. If you are not active in the industry then you are going to miss out on a whole lot of fresh stuff. The industry changes in an instant so you need to be on top of your game all the time.
Only a few weeks ago there was a big announcement about how you could no longer perform Page Rank sculpting methods throughout a site. For a long time webmasters and SEO's have been adding the nofollow attribute to external links in order to pass the page rank flow on to other pages. But Matt Cutts indicated that this does not work and has not been working for a long time.
He indicated that if you for example have 10 links on a page and no follow five of them; you will actually lose 50% of your page rank juice. This has shocked a vast amount of people simply because of the fact that they thought they could redirect the page rank flow to the other pages, so instead of each page getting 10% link equity they would of instead have got 20% for each page that was not nofollowed.
There was a huge uproar in the SEO industry, but personally I feel that too much fuss has been made over this, the reasons I say this is because it is simply common knowledge to design and structure a site in a good way. I personally have never really been a fan of the no follow attribute, instead I look at pages and if I think they have too many internal links then you look at stripping them out and structuring the site correctly. Again its part of usability, and that's what Google have always said, don't do things solely for search engines.