It would be pretty pointless. All the altcoin spam would just leak out to the main boards.
I disagree. It was only a matter of time before the number of altcoin posts outside the altcoin section dropped off dramatically after we became ruthless with moving the threads to the altcoin section, and I expect the same would happen with them being removed and only a dedicated altcoin forum (there are a few already) would accept them. So I'd expect a few months of outrage and noise followed by an eventual quietening down of the whole forum.
I guess that's a good point. Of course, we would lose quite the percantage of the user base, however that would reduce the amount of spam.
Is it possible to forbid altcoin discussions/topics and delete the altcoins categories from this forum ?
If theymos wanted, yes.