It's purely psychological. I'm like a rat in a maze going after the cheese. It's a gratifying feeling to see your "rank" go up after your three months of hard work. It doesn't have a whole lot of effect on serps but the psychological effect is tremendous.
If it is all psychological, that would suck because I can think of a lot of other activities that would be better for my psyche ...
From - http://www.google.com/technology/ Heart has no direct relation to our body and our live or something....
Don't know if this is correct but my serps has shot up since approx Dec 29th. Seen approx 60-70 extra pages indexed too. Someone on another forum said this was due to google expanding it's suplemental index program.
The PR is not updated in one day for all sites, I think. The whole process of updating the global PR of all sites takes around a week. From what I saw in the last (and the first in my webmastering life) PR update is that you may get a good PR on it, but it may disappear or change in the next few days. I have experienced it myself on one of my "crappy" blogs. I've got PR3 in the first PR update day, but it dropped to N/A in 2 days (which is the way it should be, because of the sites' "crappyness" ).
Right now all algorithms are stabilizing from recent goofups. So do not expect PR update sooner. I am happy with my PR 0 even it it happens sometime soon I will not loose it any further.
i think my pr wii go up, because my site is new, it has a pr of 0, i cant have anything less than a 0
I think PR update will come at the end of the month I hope google will give sites back some of the PR they lost in the last update