martinibuster - 6:44 pm on Dec 9, 2010 (gmt 0) [edited by: martinibuster at 8:17 am (utc) on Dec 10, 2010]
all links were pulled as soon as changes were observed
That's a good video by SEOMoz describing the burst effect. It's a well known phenomenom where Google allows a site to temporarily pop into the top ten based on newly acquired links (paid or unpaid).
Google's basis for doing that is that a site acquiring new links may be temporarily noteworthy, as when linking to a site goes viral, or a site is the center of a news event.
The burst effect may depend on the quality of the link. On average I see some movement within a maximum of two weeks. However that's just the burst effect and is temporary. SEOMoz pulled the links within days so there is no way to know how permanent (and useful) the effect of the links were.
Between two weeks of acquiring a link (PAID or UNPAID) and three months there will typically be a bit of bouncing around. After the three month point, often longer as all the links get settled in, you will then see your actual ranking position.
[edited by: martinibuster at 8:17 am (utc) on Dec 10, 2010]