MSNP was a neat little protocol. Messages were sent as mime messages. They did have a max message size, but the official client would ignore any headers it didn

MSNP was a neat little protocol. Messages were sent as mime messages. They did have a max message size, but the official client would ignore any headers it didn't know about and any mimetypes it wasn't expecting. This gave third-party clients a lot of ability to extend the protocol. For instance, I hacked in avatar support in Gaim (aka Pidgin) when I was maintaining that support. MSNP8 is when all the terrible MSNSLP (MSN SLP-Like Protocol) stuff began, with the binary packets. Spent a couple months figuring out the content of those packets... And while avatars were part of the protocol at this point, custom content was no longer as viable. I can understand some of the reasons they wanted to change it, but in the end, I think they ruined a decent (if imperfect) protocol.