He's been active on Reddit for years (he deleted history). Doing the AMA is related to the recent actions of the trustees to liquidate a large portion of Bitco

He's been active on Reddit for years (he deleted history). Doing the AMA is related to the recent actions of the trustees to liquidate a large portion of Bitcoin. The amount liquidated is apparently enough to reimburse account holders with the USD value of the BTC lost at the time. Mark has no control over the trustee actions. The details of the liquidation are unclear. It's reported that they weren't sold directly on the market, but nevertheless extra supply has almost certainly had a dramatic effect on Bitcoin price. It's one of very a few examples of a particular action/event having a direct impact on price.