It did happen on SO, SU and SF: http://blog.stackoverflow.com/2010/08/the-death-of-meta-tags/.
So shall we follow? beginner is the most used tag here...
I tend to agree with Jeff. Some of the posts tagged "beginner" are not exactly easy questions. Tagging is most useful when you want to search for answers on a particular topic. Anyone searching "beginner" is not going to find the results very useful.
I am not in favor of a "beginner" tag (nor an "advanced" or "intermediate" tag for that matter). I think the use will be inconsistent--some people, perhaps new users might use the tag as a shorthand for "pardon my ignorance, but...." while the same question by someone who has an active history on this Site is probably not interested in seeing their tag profile with a whole bunch of beginner tags and so they stay away from them--likewise, for answering them.
Aside from that, some of the best answers i've seen on this Site are to questions that were or should have been tagged 'beginner'--the OP might have been a beginner, but clearly it was not a beginner who answered it. So why have a tag attached to that thread that is a synonym for "easy?"