Welcome to WebmasterWorld Guest from 184.108.40.206
1. The update of either backlinks or PR is a reporting update ONLY. Neither update affects rankings, but they may disclose more information to you about ranking changes you've already seen.
2. PR updates are not the same as backlink updates. PR is update about 4 times a year, and backlinks a good bit more frequently.
Also, backlinks reported publicly via the link: operator will be significantly less complete than backlinks reported privately in your Google Webmaster Tools account. I assume this post is talking about the link: operator, correct?
You can't use this data for much more than sideshow entertainment. Possibly learning a few of the sites where your competition has backlinks might help, once in a while, but I'd rather go elsewhere for more complete link data.
Anybody up for creating a 12-step program to combat "Green Bar Addiction"?