In case you haven't noticed it there is a new chat tab at the lower left of your screen that replaces the old shoutbox. It is disabled in mobile mode, currently. Be cool and use it.
There is a new IM system, too. Don't be afraid to chat it up. It's also possible to share files with one another (200mb limit), the files will auto-delete in 300minutes. There is no need to upload your files to a website and then link it, you can now do it directly.