One thing is becoming very clear as unified communications becomes a reality. Presence in the portal must allow for voice conversations to be initiated. At present this is likely to mean that any presence based solution must recognise a client on the desktop and utilise the features of that client. Today Microsoft offer this but IBM do not [I would guess IBM are taking steps to remedy this].
On the other side of the coin I also expect to be able to start and IM and chat with someone without a thick client on the desktop. Today IBM offer this functionality and Microsoft (correct me if I’m wrong here folks) don’t. In the B2C portal space where authenticated customers access the environment I’d expect the customer to be able to IM me, I’d also expect to be able to IM someone from any machine with or without the IM client.