Strange then, that no one just answered:
RS is Reel Source, a tracking service (quite poor one)
RS Futures are tracking numbers from RS for future openers, i.e. beyond the coming weekend
There really is little point in looking at RS numbers, as they are only helpful for those who have no clue at all - as to whether an opener might be a blockbuster, or a film with very limited appeal. Those players who have as little clue as that, may get an inkling from looking at RS figures.
Looking at RS numbers is also popular with daytraders, as they know that people are going to react to those numbers regardless.
Then there's also the RS/MTC rule, which was explained a little further down this board. MTC stands for Major Theater Chain, btw.
Hope this was of some help (for any reader, not just the one who posed the question - and in a way that probably had many people opening the post, believing they'd see the actual RS future numbers.. :-)Ā )