> For example, email is federated. You can set up your own email server, and then send emails to people with their own email servers, or to people with Gmail or Yahoo! accounts.
Gmail actually does control somewhat inbound email by restricting certain mail and flagging it as spam according to their own arbitrary definition of spam. Oddly that even ends up flagging mail from one gmail account you own to another gmail account (both @gmail and @domain with google apps). And even in cases where it is clear there is an existing relationship between the parties. Other providers do that as well. And there is not an easy way to prevent it from happening either as a sys admin or a user (there are jump through hoop ways of course). And ultimately yes they do treat email (despite my own example) on their own network differently than email coming from a domain outside their network.
Gmail actually does control somewhat inbound email by restricting certain mail and flagging it as spam according to their own arbitrary definition of spam. Oddly that even ends up flagging mail from one gmail account you own to another gmail account (both @gmail and @domain with google apps). And even in cases where it is clear there is an existing relationship between the parties. Other providers do that as well. And there is not an easy way to prevent it from happening either as a sys admin or a user (there are jump through hoop ways of course). And ultimately yes they do treat email (despite my own example) on their own network differently than email coming from a domain outside their network.