iMessage seems like an odd choice to single out for lock in though. This is a whole network, I doubt it will be integrated directly with services. There’s not any precedent for anyone else doing that (besides maybe Facebook with their phones). Despite the fears about net neutrality.
Apple's a corporation like any other, and they're not above a little bit of vendor lock-in. Plus, given the low data rates this will support, this can only support a limited subset of Internet access.
