Search Engine Roundtable has reported the possibility of Google Valentines day update that might take place at various Google data centers.
According to a WebmasterWorld thread there are early signs of updates that might take place:
A well known rank tracking service is showing a huge spike of changes for yesterday.
Looking at various datacenters it looks like Google is "testing or comparing" different series of SERPS, at least for the keywords I'm tracking: September set of results, late october, Christmas time and January's SERPS. Perhaps Google is comparing the filter/penalty/alogo changes we have been seeing against its results from pre-September.
Search Engine Roundtable comments on the thread:
Let me stress, this is very early and that Google always updates their results – daily. But this seems to be a larger update.
However comments to Search Engine Roundtable's post has a completely different story to tell.
Matt Cutts comments :
I'm traveling, but I'm not aware of any big update supposed to be going on. The collective opinion of the speakers' room here is that it's not an update.
Read the complete post to catch the story.