As "Big Brother Fans Blog" tells us in their post " When Do The Big Brother 16 Live Feeds Start?"
"while tonight (June 25th) is indeed the Big Brother 16 premiere, the live feeds will not begin until tomorrow night (June 26th) following the CBS show. The good news is there is still time to get the special early bird price;on feeds and save 20% before they go live, but this is your last chance!"
So, there you go:
If you subscribe to the BB16 live feeds tonight, you won't get any content now. BUT, if you wait too long to subscribe you are going to end up paying more.
If you think you might want the live feeds at all, you should probably go ahead and do it. Even if you can't see anything special right away!