Happy Birthday, Lady Gaga! Topless photo, quoting Karl Marx?

Lady Gaga -- still on her world tour -- tweeted a provocative -- on many levels -- birthday message for her "little monsters" this weekend. Her 24th birthday is Sunday, March 28.

The major buzz is that the photo looks like she might be topless. Wow, how shocking! But some people are more interested over her "communist" undercurrents.