How Does a Money Market Account Work?

[Degen]

I understand there is a bit more risk than standard savings accounts...why?

Also, how do these companies make money on the deposits while protecting against the short term need for withdrawals etc ?

Using ING and Emigrant as examples, how much do these companies figure to profit on deposits if they are giving out 3.75-4%?

Who manages one of these? Is that a job title?


Any and all input appreciated.