We kind of post in bursts... meth users, that is. Actually I was surprised about this very same thing the first time I looked at the forum stat page. nosaj_thing may be right that heroine is more popular; it's usually the same dozen people posting again and again in the meth thread with an occasional new reviewer, if that's any evidence one way or another (never looked at the heroine pages and don't know how many people post regularly... opiates feel good but aren't my thing).