I've seen many floats in the last two weeks - a few up, a few dow, a few new pages, a few pages dropped. I don't think they are doing the traditional "one fell swoop updating" and instead, updating things on the fly. When we see major changes, they've just tweaked the algo.
Does anyone know have a guess when FAST is going to do the next update. I was wondering, due to their new paid submission program if they were going to hold off on updating so that they could include as many paid indexed as possible. I have noticed a pattern with any search engine company when they get ready to do a face lift or a paid submission, they generally hold off on the indexing.
The update of July 16th was (for my site) a fairly complete update. Fast spider is back today again. This indicates either on-the-go continuous updating Brett talks about or a a fairly frequent update (2 weeks frequency is my guess).
I do not see any holding-off their indexing as probable - it is a dangerous game to play. It may bring some more clients to paid submits, but it may also drive more users away to other, faster search engines... (Do you remember altavista earlier this year?)