@musicman I can think of a reason why #Pump.io may not wish to add a visible version string (yet). Up until the E14N servers collapsed, they were all running outdated versions (and way behind now, over a year later).
On the other hand, it makes error reports a lot more helpful. And it makes it easier to see when federation-breaking changes can be switched on.
In general, I'm in favor, but I think any pumps still in existence will need to be running the current year's code.
@sonyampump.io has private messaging, followers-only posting, federated identity so you can run around on other servers and comment using your home id, the API is lightweight and very consistent and understandable in comparison with GS+Qvitter (I hear), and it's the basis for the Next Big Thing, #activitypub.
pump.io was built in a few months by one guy though, and GS was built in a couple of years by several full-time people, so there are still quirks in the (actually intentionally) limited web UI. pump.io works best with a client.
@andstatus does a decent job. I'm not going to complain, because I still didn't file those bugs since last I complained, so the buck is with me. It's mostly about message formatting, other than that it's an awesome client for both GS and pump.