>As for monetizing, that's probably with ads, as usual, but you have to be careful about when and where to put them.
How about analytics? For each person who writes about me, I could pay to see where in the world they lived, how long it took them to type in the three words (or even watch a movie of them typing them in), whether they clicked the link that was on my Facebook or the one on my Twitter feed (based on HTTP referrer), etc.
If you were confident you could give each user the ability to see this information for 1 user for free, and then have them pay if they wanted to see it for the rest of the users.
Hmm, that's interesting. Very popular users might find some use for that kind of thing. For example, up and coming music artists trying to build a following and connect with fans maybe... I definitely think sites should consider charging when and where possible, but sometimes there is good opportunity for it, and sometimes not.