It seems that Philipp Lenssen has figured out how to surreptitiously add searches to my Google Search History:
If you have the Google My Search History activated, check if you find an entry today for the search query “Google Blogoscoped sneaked in through the backdoor.”
I checked mine, and lo and behold, that query was listed under my “Searches with no clicked results.” The comments reveal that Philipp is loading up a hidden iframe within the page with the Google query preloaded. The search gets added to your search history when you load his webpage.
It appears that we can now add to the concerns about personalized search the fact that some remote third-party can maliciously add potentially-damaging items to my search history.