I remember to have upvoted the question and answer https://askubuntu.com/q/97569/6969 and after migration to meta I thought, good question and answer, let's upvote it.
After that, I realized that I've already voted those posts before as I can see on the main site. These upvotes are added to the previous ones as can be seen on Can I use my Canonical/Ubuntu.com or Launchpad account to post and / or answer questions here as well?