And so there's the answer -- you can use the tag for links others contribute to your pages (as with forums, comments, guestbooks) or for links you control but for some reason don't want to be counted by search engines for ranking purposes.
So coming back to:
Will these links (with the tag) count regarding PR? Example: you have 10 links on a page, 5 normal, 5 with no follow. Will Google divide that page's PR among 10 or just among the five links it can follow? It would make sense to divide only for the 5 normal links but who knows.
Yes, that's correct the way I read it (and I also addressed this in my story). If you wanted to horde or channel PageRank like this, you could.
Of course, Google itself is likely already discounting some of your links already, say in the nav areas, those repetitive across the site and so on. The oversimplied "Google takes your page PR score and divides it among all your links" is exactly that -- oversimplified. Exactly how they do things we know has changed, and they've dropped plenty of hints that certain types of links are discounted.
As Mikkel noted, this also isn't a blog thing. IT'S NOT A BLOG THING. Folks without blogs, rejoice -- the world does not revolve around them. This is a tool for any type of web author.
Conceivably, Google could try to spot certain links that seem to be on blogs -- major blogging software leaves certain traces -- common URL styles, CGI calls. So down the line, if they wanted to treat "blog" links with nofollow different than non-blog nofollow links, they might. But it would be a guess -- and they'd make mistakes.
I think that the sales dept. is not going to be happy and they might have the final say.
I've done some back story before on those internet.commerce links, but I'll revisit this. They predate Google and reliance on link analysis. Believe me, I know -- back when I used to roll the site myself, it was always a pain having to update them when they came to me.
I don't sell the links nor handle ads on the site, fortunately -- which is nice. But I have checked to see if they are sold with any suggestion that they'll help an advertiser with search rankings. Jupiter has told me emphatically that they are not positioned that way.
Some advertisers might by them for that -- but as I've also posted, it's pretty easy for Google to see the same links, in the same styles and places, across the entire Jupiter network -- and then do discounting as it sees fit -- just as it might with nav elements. So I certainly wouldn't buy them thinking they'd give a ranking boost.
But bringing it back home, what is annoying is that a preexisting ad program suddenly gets called into question because a search engine emerges after the program started, makes noises about "don't buy links" and suddenly, people question if you're doing something shady. As a result, you have to start considering if you need to jump through hoops. Should I redirect all the links so Google -- should it start checking things -- decide that I'm not trying something on.
Please. What a pain. What an annoyance to constantly have to wonder if something you think makes sense might have to have some wider search engine worry. And that's why I did that earlier article about wanting an "ignore" tag. We shouldn't have to be paranoid about what search engines think about our site -- but at least with this new mechanism, I can explicitly say, no -- these links aren't trying to spam you.
So yep, I'll be suggesting to Jupiter they consider this type of thing, if only because if they implement it, I don't have to hear questions about a link program that existed before Google