Champions Online implemented something which, while sounding good on paper, was not terribly utilized - sometimes while wandering in a zone, (mainly the main hub zone, Millennium City), you'll get a popup that you see a crime in progress or something out of the ordinary, and can accept a related mission. The problem is that they are neither rewarding nor interesting enough to be any sort of reliable source of content. I much prefer the general reliability and accessibility of CoH's radio/newspaper contacts. Those could stand a bit of customization and enhancement, though - like choosing the enemy group(s) you want to fight, excluding hostage/escort missions, and so on...