Sony answers PS3 firmware 2.4 questions
Trophies not retroactive, or mandatory.
Sony PSN boss Eric Lempel has sat down to address some questions about PS3 firmware update v2.40 on the official US blog.
The patch, planned for release tomorrow, will finally introduce in-game XMB functionality and trophy rewards.
According to Lempel voice-messaging is being "evaluated", you will have to quit your game to access the PlayStation Store and trophies are not necessarily mandatory but should be included in as many games as possible.
Trophies will make a noise when you earn them and you can compare them with your friends who are on or offline. They will not be retroactive, so you will have to replay games to unlock them, and they will be limitless in each title but draw from a capped value pool - so unlocking all of them in one game will be comparable to unlocking all of them in another.
Head over to the official US PlayStation blog for a full roundup of questions and answers, and to find out what cheese Eric likes best.