To me, this looks like someone with a lot of money deliberately trying to ratchet up the price of Bitcoins for reasons unknown... which means that as soon as he decides it's no longer worth his time, all of that support at $2.90 will vanish, and who knows what'll happen to the price then.
Yeah one such 'unknown reason' could be that a genuine buyer and long-term bitcoin bull is putting it there to give the opportunity for any big sellers to sell into it.
The placer of that wall may well be putting in many smaller bids in front of it all the time to pick up coins.
By having a wall just below where they are buying, they give themselves feedback that their buying is not driving the price to excessive levels, because presumably big coin-holders would have dumped into it already if that were the case.
Without the wall - their average buy price may in fact have been higher due to coin sellers merely trickling them out because the sellers don't want to risk crashing the price.
You could argue that the buyer should test the price, or try to get a lower price, by 'vanishing' the wall altogether every now and then - but it's possible that a sudden drop is not in their interests either, as they'd rather their own buying activity set up some momentum for some subsequent gains and they'd rather not contribute to bitcoin instability or another stretch of decline.