For the past few weeks I have been prompted by Picasa to link my photos to my Google profile. This nagware appears every time I visit Picasa. It also appears I cannot comment on even my own photos without linking my Picasa account with my Google profile. I got rid of the nagging (or so it seems) by deleting my Google profile. It seems I've done this before.
Google has no regard whatsoever for its users' privacy.