No, but Yahoo IM does. You move to "mobile" state, and it converts IMs to SMS to "push" to your phone. It does so by sending to you via a unique phone number, part of which is a unique identifier for yahoo, part based on where the person is in your friends list. It tracks you by caller ID. You can add that to your friends contact as a separate number and it will show their icon as the contact.

Handy for places where you don't have data, but still want to IM, as long as you have unlimited SMS. I've used this many times, and it works pretty nice. With a script, you could even find/detect these types of messages on the fly and change them in the database to show up as IM chats later if you prefer, vs SMS from the yahoo IM gateway.

Uh... No?! I don't know what you're doing, but MY contact list isn't being sent to anyone. There's a big difference between a service knowing who you're linked to with them, and having a copy of your contact list. About 10% of my friends use IM, so sure, Yahoo or AIM or what not know of them. None of them have my grandma's number and home address. If an app is sending your contact list to scan for people you may know to link to.... that's VERY different than connecting with a known list of people you've added and connected with on your own.

I concur with the majority on this one: There are dozens of supported free/open chat protocols out there. Paying for or wanting to use one that's closed seems silly. I get that your friends may use BBM because they're locked in on their device. But to reward that by trying to use it too seems counter productive. Tell them to ask BBM for a gateway to another service. If enough people ask for it, they'll probably provide it.