Got a link under my albums saying
<<Google Site Stats – send feedback>>

Links to:
[ https://services.google.com/sitestats/en_US.html?cid=1070786884]

Three things:
What is this? (i'm tired and don't understand it)
Is this new?
Why does the linked to page say ©2004?

(http://picasaweb.google.com/mrrix32/OtherPictures/photo#5034104605748614002)

This seems to be a really old/outdated/pre-Analytics page.

So why has Google just put it on to a new service?

This comes from their standard conversion code for Google AdWords. I guess they're trying to monitor how many conversions they're getting from people clicking ads for Picasa Web Albums.