It is open, but most[1] people are going to use the Google-provided servers. Businesses who want to keep their data safe can have an internal wave server, but

It is open, but most[1] people are going to use the Google-provided servers. Businesses who want to keep their data safe can have an internal wave server, but these aren't the kind of places which would allow employees to use Gmail for their business communications... [1] Wild assumption, but I expect that the numbers will bear this out.