For mobile, the switch from Google Talk to Hangouts was little more than a facelift. The deeper issues reside in back-end utility, and inside desktop applications. Google Talk inside of GMail will allow for SMS or calls. Hangouts will not, currently.
Verizon Messages 4.0 brings SMS messaging to phone, tablet and PC
Starting today, you no longer need a Facebook account to use Facebook Messenger.Yes, you read that right. With this unexpected move they are now entering the hotly contested arena of SMS replacement apps. All you need to start is a name and phone number, and you can communicate with anyone in your contact list.