Yes, I meant a direct message too - like a flag - because it would discourage spammers. I didn't unpack it, so it was ambiguous.
I'm not sure if the "10,000" reports would happen; have to try it and see. It's probably more like bug-reports, or 37signal's "feature requests" (that they read and throw out). And, if you fix the typo, the reports stop. :-) It's hard to judge, but I think you'd have to be massively popular to get even one or two typo reports. But I don't know: need to do the experiment.
Maybe a lower-cost solution would be just to add "prompting" text next to the comment box, something like: "typo corrections are welcome", to encourage people.
Typo reports (bug reports?) aren't that common: for example, I made a comment on a typo to Tim O'Reilly's recent blog - but no one else had.