Collective
Here you can find some recommended Jabber/XMPP service providers that offer to host an XMPP server for collective use by a group or organization. They also allow the collective to use its own domain name for Jabber IDs like this: name@organization.org
.
Conversations.im
Conversations.im is the commercial offer by the Conversations project. Learn more about how to register and link your own domain name on their website. Their services are hosted in Germany.
Hot-Chilli
Hot-Chilli is run by an IT company from Germany and has been running a free XMPP server since 2005. You can learn more about their Jabber service here. It is possible to connect your own domain name to their XMPP server.
Snikket
Snikket is a project started by a person from the Prosody project to provide a unified app experience and easy server hosting. Learn more about their goals here.
Tigase
The Tigase XMPP project also offers professional server hosting for large organizations.
Others?
This is obviously not an exhaustive list and if you have a really good recommendation please contact us here.
If you are the server operator of one of these services and disagree with being listed here, please contact us as well.