Go to "service" section and you may get some free cash to do something, for example : writing a feedback / comment will earn you $1 in bitcoin within 1-2 minutes, thread
https://bitcointalk.org/index.php?topic=678875.0or find another good offer from other members, there are new offers almost every day
For the thread you linked, I believe the offer is over already, as it said "New offer starting 2014-07-07 until 2014-07-17"