AMP still purges. It just depends on what boards you're posting on.
For social boards, the slower the board gets, the longer posts take to purge.
From what I can tell, it seems like the social boards are set to have about 200 topics minimum, so as people post less, the amount of time topics are allowed to linger before purging gets longer. PotD has been getting slower and slower, so the cut-off has gone from about 10 days, to about 2 weeks, and now it's around 18 days. Topics on RI last slightly more than a month.
Topics on CE still last about 3 days (which was the original purge rate), but all of them are terrible so it doesn't matter.
The way things are going, I'm assuming we're going to hit 3 weeks soon.
"Wall of Text'D!"
--- oldskoolplayr76
"POwned again."
--- blight family