An early WebmasterWorld thread is reporting very early signs of changes taking place at the various Google data centers. Often, these types of threads tend to spot a Google update that is about to take place. But it would be cool if Google gave us a Valentines Day update.
Let me stress, this is very early and that Google always updates their results - daily. But this seems to be a larger update.
Here are some of the reports from the WebmasterWorld members:
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.
Again, it is very early, but I will track it.
Forum discussion at WebmasterWorld.
Update: Matt Cutts commented below that he does not believe there is an update taking place. Plus, he has a room of SES speakers who backs his opinion. :-)

Comments:
Matt Cutts
02/14/2007 06:18 pm
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. :)
Barry Schwartz
02/14/2007 06:19 pm
Send regards to the "collective opinion" over there. Enjoy London!
Jan
02/15/2007 10:09 am
I am responsible for several sites we regularly Google datacentres and last night saw big changes and huge descrepancies in number of pages indexed. One of my sites normally has 750k pages, 20 out of 40 datacentres showing 260 (yes 260 not 750k) pages! Another site normally has 330k pages also showing 260 pages across 20 datacentres. Our competitors sites also showing similar bizarre results. It is hard to believe nothing is happening.
Roland
02/18/2007 01:51 am
Wow - Today I had a 90% drop in organic traffic as my page rankings on google plummetted.
Christa Pellicci
01/09/2008 12:13 am
when I wake up in the morning their is my Valentines day bag already for me with lot's of goodies waiting for me this year i'll be home eating chocolates out of a box, without No Valentines day lover, nope i have no boyfriend how sad i'm 28 years old. hope i can find one from Christa