You can still invite people to look at your base, you can trade items, you can help people build or ask for help, you can chat with everyone... so yeah, it's definitely multiplayer. All made easy with enhanced portals.
someone's stealing your karma: http://www.reddit.com/r/feedthebeast/comments/22r3bb/thermal_expansion_jetpack_mod/
>Releases ComputerCraft 1.6 >Breaks all mod compat while a lot of modders are trying to get 1.7 updates done