I don't think is there a way to eran free bitcoin,at least a good amount, not just a couple of satoshi.
But if someone's got many free-time all day,it is possible in several ways.
Best way I think is signature campaign. It will likely remain this as long as the forum allows them.
For one if doing it right you get the you are posting as normal. So does not cost you additional time. If you are doing it just to get posts you doing it wrong. But it pay's better (full member and up) then any faucet will.
Used right it is honestly a good system. Just don't abuse it.