Now the preferred method is postings in various forums and then playing on-line game while waiting for someone to post the answer back in the forum.
Of course the title has to be carefully constructed so some innocent users would fall for it and give the answers. I can think of a few.
"Hardest problem: none of my classmates has an answer"
"Professor said this would take a whole day to solve"
"It simply cannot be done, I give up"
"I bet no one can solve this, my teacher can't"
The lists go on.