Has Google danced this month?

Quick question. Has Google done it's dance this month? The reason I am asking is because as of yesterday I moved down quite a few positions on Google. I have gotten about 300 or so more links from other search engines like Altavista and MSN and changed some of the words on my main page the other day. I went to do a search on Google today and noticed my site had moved down a couple pages for all my keywords! If Google hasn't done their dance yet and I change my text back to the way it was will Google place my site back where it was? or is the Google dance just when they add everyone's links onto their link popularity? Can google increase or descrease your search engine rank if it hasn't done a dance? If so, how often do they do this? Thanks!
________
Suzuki RG500

I don't think Google is "dancing" anymore. They're doing more like rolling updates.

And yes, your rank can change when there isn't a major update.