In first place, I thought I might keep them in. But, I was unsure about a good guideline how to keep them up to date.
Let's take for instance @since. What does this exactly mean. It may mean when the function or class was added. But what if the signature changed? Is this a different function or still the same? Are this still the same @authors?
I came to the conclusion that they are hard to maintain and git/subversion give me the info I need in a way more convenient way. So I removed them with this commit.