By the time AIM is irrelevant, AIM and its AOL subscriber-only predecessor will have been important for at least two decades. That is not a short period of time

By the time AIM is irrelevant, AIM and its AOL subscriber-only predecessor will have been important for at least two decades. That is not a short period of time, and its demise could have easily been avoided with a tiny bit of foresight, not that I would've done any better. Facebook won't be around forever, but it's hard to see how it would be dethroned within the next decade.