Ok. So, do you think it is a kind of payment for advertising the site?
That's exactly what it is. That giveaway thread is one of the most active on this forum. Currently 61940 posts and 1685735 views. That's just from signed in members, from the forum advertising stats there is 10 times more traffic to this forum than that. It wouldn't get noticed at all if it was hidden 3 pages down on the board. The whole OP is a huge advert with graphics, everyone sees that the first time they visit the thread. It's partly down to the forum rules that forbid someone bumping their own thread more than once a day and also only allowing incentivised posting in the games and rounds board.
It must be working for them as they have been running it since July 2013 and just for fun the first payment I got when they used to credit it daily was:
0.00500000 SYSTEM From Admin Nov. 6, 2013 - 1:09 AM
But I dont think members are able to collect this like faucet, just post daily then withdraw it once they reach the minimum withdraw. Especially with the latest btc price which is so high, if 777coin let this kind of activity means they are doing charity and it requires a lot of btc.
It's not like a faucet or for charity, they are paying you to bump the thread so it is always on top.
Do note there are no restrictions what so ever! So you may withdraw at anytime you wish
How can you come to the conclusion you did after reading that? Oh, and BTW there is no minimum withdrawal except you have to pay the transaction fee.