i think it helps indexing

I for one completely agree on no-follow for blog comments. Most people don’t have time to moderate every blog comment dropped and as you said the spammers take huge advantage of this, which can lead to you unknowingly linking to bad neighbourhoods..

This is definitely one area where no-follow is useful for external linking. Keep up the great blog!

With regards to your no-links algo I have a few notes:
A. Google collects valuable information from users through the various services such as gmail, toolbar, reader and most importantly - Analytics.
As of now, they do not state whether they are and/or intending to use it for their ranking algorithms or not. I can only guess that they most probably are testing that and will use it in the future to a certain extent.

B. There are quite a few patents google registered with regards to link evaluation. One of the most interesing subjects is the temporal linking algorithm which takes into account the time factor and link freshness. We’ve seen this in some cases where new links “boosted” our rankings for a while, and then cooled down. So here’s another direction.

With regards to your second comemnt - Yes, I also use nofollow in my blog comments and that’s for 2 main reasons:

A. Even if I don’t like it, this is the new rule in our game.
B. It does reduce in a way the interet of comment spammers from spamming me continuously.

You can see that in the posts I do not put nofollow, and actually at this point I don’ think I will, as I control the content myself. In websites with no or little moderation such as UGC (user generated content) sites such as flickr, delicious and so on, the little/no moderation creates a huge spam loophole which is expoilted by blackhats.

Links make up the web… so who knows what the future holds! The only way to escape this mess is for the big search engines to work off an algo that does not rely on links. Can you ever see that happening????