Dramatic ranking shifts

[znotes]

I’m starting to notice some interesting behavior in Google rankings. It seems like most days, rankings move around but movements are relatively small. Then, maybe once or twice a month, there are days (like today) where everything seems to shift around in more dramatic fashion. I don’t know if it’s algorithm updates, or maybe they do light crawls every day and heavy crawls a few times a month..?? anybody have any idea what is behind these big waves of ranking changes?

[Malarowski]

I experience exactly the same, often keyword go up and down by 1-2 every other day until they suddenly leap up 10 or so and then drop 2-3 where they stay. Your theories both make sense and it might be just that the crawl gets to your site and does an in-depth 'scan' of everything.

[GregFindley.co.uk]

I've seen some more dramatic shifts over the past few days for UK results at least, from what I've been reading on various forums/Twitter I think there's been some algorithm updates, as a number of sites/webmasters being affected.