Currently the default options for people are texting and Facebook. You do however have the ability to add other plugins and the developers have indicated that there's more on the way.
If they could add Google's Hangout to the mix, it would be awesome. It's getting there slowly.
If you'd like to check it out for yourself, head on over to the Google Play link.
You can also visit the official page at http://www.disa.im/