The expansions Bloodmoon and Tribunal add 100+ hours of gameplay by themselves,  and they are no where close to the size of Morrowind.  It has like 400 hours of gameplay,  He said that it is a single player MMO (Massively Multiplayer Online) because it open-ended gameplay and its NPC's because all of them are different.  
 
;D  O_o  I like my paragraph.