helpnow - 6:57 pm on Apr 5, 2010 (gmt 0)

It is feasible that the differences of opinion on whether or not caffeine comes with an algo change may be as cangoou alluded to:

The pre-caffeine SERPs we see may be driven by a stale set of 3-month old data, and the caffeine SERPs we see may be driven by a more up-to-date set of data (how up to date, I dunno, I suspect better than 3 months old but not still not fully current).

So, it may be when "caffeine" is spotted, the SERPs seem different, and this is a legitimate observation... Even if caffeine isn't directly an algo change, it may be paired with a newer data set accounting for the SERP differences we see...