Email will probably be the last to go, when the last user of it finally gives up and moves to gmail so they can continue to communicate with their contacts or maybe they give up entirely. RSS (an open content syndication protocol on top of HTTP, which I think is a nice way to illustrate that it is possible to use HTTP as a layer and play nice at the same time) is already an endangered species, XMPP support is slowly but surely being removed (just imagine a phone system where every number you call to may require a different telephone), NNTP has been ‘mostly dead’ for years (though it still has some use the real replacement of usenet for discussion purposes appears to be Reddit and mailinglists) and so on. The only protocols that are developed nowadays that are open are typically related to plumbing (moving bits of data around), not application level protocols which determine how a whole class of applications around a similar theme can talk to each other.