More importantly, it's more effective because it's less likely to be detected.
It still shouldn't be patentable because there's prior art involving a bunch of systems with various forms of audience selection such that how to implement this specific set of audience selection rules is obvious to most software developers. Patents cover how, not what, and they do not cover inventions whose implementation is obvious to most experts in the field.
This is (ahem) patently not true; there are plenty of patents whose implementation is incredibly obvious. Insultingly obvious. As in, "Did that company try to patent string comparison?"
Look up the "standard network byte order" patent, for instance. It's now expired and was never enforced. The friend-of-a-friend who got that patent was heard to exclaim "I can't believe they gave that patent to me!", which should tell you a lot about the quality of the patent industry then -- IMHO it hasn't changed for the better.
They should not be, and somebody should probably be lobbying congress to address the patent office not being sufficiently strict.
I'm not entirely sure why, but there appear to be perverse or at least badly aligned incentives for patent examiners, and it would appear they only look for prior art in specific locations, and these aren't the ones that the industry uses.
So you get situations like someone getting a patent for putting structures on multiple lists at a time (e.g., a lookup list, and an LRU replacement list, and maybe a list for keeping track of locks) and this is something that people have been doing since rocks were young, but some nincompoop at OraGooSoftBook got a patent on it because these structures appear in OS textbooks or maybe Knuth and not anything the examiner encountered in law school, or any legal publications. And now FaceGooSoft has a legal lock on code you wrote (hey, you did diligently read all the patents relevant to your industry before you wrote a single line, just like everybody else does right?).