Anna is probably more famous now; however, Serena's popularity is still evolving. Also, we aren't sure how Serena is going to fare off of the tennis courts compared to Anna. She may actually eclipse Anna in that department.
We do know, though, that their names should not be mentioned in the same sentence when it comes to tennis.
-one of those "bad" Williams fans that everyone keeps talking about
OFFICIAL BLACKSMITH OF THE ROYAL COURT
I don't mind straight people as long as they act gay in public!