I know this is kind of off topic... but does anyone know for a fact why Apple didn't make Siri compatible with the iPhone 4? It doesn't make sense to me, considering that the 4 and the 4S both contain 512MB of RAM. Is it purely because of the A5 processor in the 4S?
It's probably because they don't have enough server capacity to handle all the iPhone 4 owners on Siri. Most of the work is done by Apple's servers, not the phone.
If they allowed all the iPhone 4 owners to use Siri it would take 3 times as long for it to respond. I'm sure they're working on upgrading their servers now, SIri is still in beta after all.
Note that this is just speculation on my part, but it makes sense. Apple could also just be greedy.