I won't deny that pot has affected my memory, but at the same time I don't blame the herb for it. There was a point in my life where I wanted to forget everything... I really just didn't give a fuck about remembering anything, and like Inferious mentioned it had a lot to do with emotional crap. So I smoked a shitload of pot and let myself forget a lot of stuff. Not my brightest hour, and I do regret having lost a lot of memories when I let them go. But I think it was a concious choice, and smoking just made it much easier. If you smoke in moderation and after your brain is fully developed (after puberty) I don't think there's much to worry about... just don't expect your short term memory to be fantastic while you're high.