Kinda like RTB, have a good control panel to use online. I loved how RTB had a place to view chat online and even talk to your players online. You could enable addons and even admin/deadmin people.
To add on to what I said:
With Steam, people have no key to use for a hosting service. Hosting services literally have handicaps. You have to provide rental keys to host under. Free rental keys after some time on the service might attract more buyers, because it probably feels like you're getting ripped off when you have to pay an extra dollar for something Steam players can't control like BlockNet did.
Edit: Also, I'd love to have another hosting service. I've bought over 1.5 years of hosting service from HammerHost and BlockNet.