You see these all the time - payday loan companies, and all that - and this is just one example. ThinkCash (http://thinkcash.tv) is a vulture lender advertising "quick cash!" lending on television through direct deposit into your chequing account. Unlike most of their customers, I looked at the numbers in the fine-print. The interest rate is 217%. (Not 21.7%; 217%.) Clearly, it is compound often - probably continually - as a US$1,000 loan results in you paying back US$2,775.9.
If you know anyone, anyone, who is in the sort of position to consider these things, stop them.