irrevocable use (aka the temporal dimension): irrevocable use is a big draw for users and developers. Open source has typically taken this for granted, since source access is irrevocable. But that may no longer be the case- what about the case where servers/services go away (either maliciously or for other reasons.) Has implications for things like server ownership and server governance.
acceptable use: even the v3 now includes some potential restrictions on use (where, for example, the network is damaged by modified clients.) Might an open service still have some AU-like restrictions, as even the FSF allows for certain integrity provisions?
source use v. API use: a service could provide source code to their servers, but still have a very restrictive TOS on their APIs (which presumably control access to community-created/pooled data, and hence are much more interesting/relevant than the server code itself.) This might even be pragmatically justified, if the service is very bandwidth intensive.