Pretty sure this will never happen. I don't think theymos wants the forum to be holding money for random people.
I had an idea about that, though I'm not sure whether I'll do it. The forum could accept BTC and in return give "forum credit", which could
not ever be withdrawn for BTC, but which could be used for ads and donations. Since forum credit has value, a market would develop with an exchange rate somewhat less than 1 BTC per BTC of forum credit. A micropayment system could be based on forum credit; receiving 1 BTC of forum credit would be just a less convenient and more centralized way of receiving ~0.95 BTC.
Micropayments are a very low priority in any case, though.