I was at a startup in 94/95 where we made something a lot like protocol buffers, with a multi-platform, multi-language (Java / C++ / COM) API on top of it. Was very friendly -- very JSON-like -- and worked really well, up to tens of thousands of messages a second through then developer-class Pentium boxes.
I think you can still go fast without being nasty. Whether there is money in it is another question.
Another real-world example: SMTP vs QMTP (http://cr.yp.to/proto/qmtp.txt). IMHO, saving space by packing bits is not really so important anymore since nearly every link has high-bandwidth. Reducing latency by reducing round-trips is huge though.
Something is wrong with the styling of that page. In Chrome, Firefox and IE the first few paragraphs overlap some of the panels on the right, making it very unreadable.
Anything from completely brain-damaged (XER) over cheap (GSER or BER, depending on whether you want widely-used or human-readable) to nasty (PER) depending on what encoding rules you use.
I think you can still go fast without being nasty. Whether there is money in it is another question.