What SDK should I use? c++

Question

I have this program in mind that I would like to attempt and create in c++. I am not sure what SDK I should use, Here is the idea:

Basically like Facebooks status' or twitter but strictly for your desktop. Window like AIM or MSN would allow you to view your friends and their current status, allow you to comment on it, etc. When someone changes their status, all of their friends get a little notification on the bottom right of their screen saying what their friends current status is. There would obviously be much more that sets it apart, but this is the basic idea that I'm starting from.

Answer 1

If you plan to release it as OpenSource, the Qt GUI Framework is very much worth considering (you can buy a commercial license too). It is crossplatform (Linux/Win/Mac) - eg. Google Maps desktop app uses it.

It will give you networking support, HTML/XML rendering if necessary, SQL and much more.

As for communication protocols, go with Greg's suggestion.

Answer 2

A good choice for a cross-platform GUI system is wxWidgets. For communication between users, something like XMPP would be a good option, because it is a platform-agnostic open standard with solid support for user "presence".