rfgdxm1 - 4:16 pm on Nov 3, 2003 (gmt 0)

>2) It is generally agreed that back-links are updated every few weeks.

It isn't backlink updates that count. It is when PR is updated, which may not necessarily be at the same time. There is good reason to suspect that PR is only updated every month or so. The reason being it is very computationally intensive to do so. Thus, by making changes on page between PR updates, you may be able to get some insight about other algo factor weights.

Caution: this assumes that PR is only updated monthly or so. If Google has figured out a way to update PR on the fly, all bets are off.