Further confirmation:
https://www.google.com/search?source=hp&ei=UaEiW_mNM86GsQXX-ZDACg&q=fallout+76+is+an+mmo&oq=fallout+76+is+&gs_l=psy-ab.1.2.0l10.254.4697.0.10982.15.14.0.0.0.0.218.1105.13j0j1.14.0....0...1.1.64.psy-ab..1.14.1103.0..35i39k1j0i131k1j0i20i264k1j0i131i20i264k1j0i3k1.0.PU8BEgVKlK4

All it is, is a Google search for Fallout 76 mmo and it indeed seems that it is one. Which is fine by me but I'll pass on this one.

I'm kinda hoping this is Fallout's "Far Cry Blood Dragon", a relatively cheap side project with resources they mostly already had anyway.

Sadly I'm worried with the online design it's likely to be very succesfull financially, even if it only turns out to be an average game at best.

(look how well they did with Fallout Shelter, though granted, I enjoyed that game a lot)