Work & Pay
Requesters post many available tasks called HITS. These are tasks that computers just can't do accurately like transcription, tagging photos, google search analyzing, etc. HITS vary, so you can find almost anything to do. The more you work, the more opportunities you gain. If you become a trusted worker for a requester, you are the first to receive work and possibly a pay raise. If you pass tests for requesters you are able to do more tasks as well. If you accomplish a lot of work in all categories you can earn "Master Qualification." This shows that you are a very skilled worker and are qualified to do pretty much anything. Workers with the Master Qualification are preferred and generally earn a lot more, but there are still a LOT of jobs that don't require it.
Not much can be said about the pay since it varies depending on the HIT and requester. Pay ranges from 1 cent to $50. Keep in mind lower paying HITs often have a bonus reward, so you can earn more than what is advertised. Higher paying HITs are usually invite only/specialty surveys or transcription but not always. Transcriptionists can do really well here. Payments are made through Amazon Payments or can be added directly to an Amazon gift card balance.
Availability
If you can't find a HIT either you aren't looking or you're being way too picky. A task is usually posted showing x amount of available HITs. x is generally in the 100s to 1,000s range.
Referral
There is no referral program.
Quick View
Pay: Varies
Bonuses: Yes
Promotions: Yes
Daily limits: MTurk, no. Certain HITs, yes.
Age restriction: 13+
