I have had a number of titles to my questions on SO edited to remove text such as
MySQL: with no explanation or notification.
I'm guessing that this is because someone thinks it's redundant since the question also has the same tag.
However, prefixes such as these help the system list relevant questions in both the 'Questions with similar titles' and 'Similar Questions' boxes.
Note that I have seen some questions related to this, but none that give concrete reasons for the current trend of removing tags from titles.
EDIT: Wow, -10, you are a friendly bunch.