Blizzard and Activision Merge

Big news today: Blizzard and Activision Announce Merger.

Activision and Blizzard have said they will form "the world's most profitable games business" in a deal worth $18.8bn

This could mean a lot, but most likely this is just an "on paper" company. I am guessing that each company will stay seperate and produce their own titles in the same manor as they have been doing. Some resources will be brought together, but I can't see any major changes out of this.