#1. I've only recently been introduced to the term by discussions on the AAR (that's All About Romance) forums wherein it is described as an alternate reality - Victorian age with a technology based on steam... haven't read any of the recent books described as "steampunk" and I don't get the "punk" part of it in any case.

#2 Have no idea when the recent wave started. I immediately thought of the Randall Garrett Lord Darcy books where the technology is based on steam (and magic).