Bill de hÓra has blogged an email exchange that he and I had some time ago in which we discussed some of the design decisions we've made at PubSub.com. The particular focus of the discussion was on our use mixed use of XML text-based encodings and ASN.1 binary encodings... As Bill mentions, I've received a good bit of heat over the years for supporting the mixed use of XML and ASN.1. Apparently, it is hard for folk to understand that it is possible to be an "XML-supporter" while still being an "ASN.1-supporter." But, after almost 20 years of this debate, (it really got started with ASN.1 vs SGML back in the 80's), I strongly feel that both types of encoding have a place in many systems. As I've commented elsewhere, on the XML-DEV list, I feel that the XML vs ASN.1 debate is really one of "computer science" vs the "human sciences." ASN.1 is better "computer science" while XML is better "human science." ASN.1 is typically more compact, efficient, etc. than XML while XML is usually much easier for people to produce and thus is often better for solving interop problems. But, both styles of encoding have their place. You simply have to be very careful in deciding which to use for each kind of interface you expose.
If you're interested to learn more about how PubSub works, see: Bill's Under the hood at PubSub. Or, the text below: