Regarding crowdsourcing and XML, I once put a dozen students to work on transcriptions of some very formulaic accounting documents. It was enough work to get them through the medieval paleography and language that I didn't want them spending a lot of time mastering XML or new programs. So, I created a simplified schema that they could easily memorize and let them insert tags in their generic word processor.
The tags (e.g. <id>...</id> for a proper name of a person; <amt>...</amt> for amount, etc.) are easily converted into TEI compliant XML with a simple search and replace macro. I wanted two sets of eyes on the transcriptions, so I had each text transcribed by two different students, but only one copy included tags. I created a couple of tag validators so they could easily check their markup. Then, I designed an editorial review utility that allows me to highlight differences between the dual transcriptions, and incorporate any of my modifications (to transcriptions or tags) into the final transcription.
The grad students who were in charge of supervising teams of undergrads worked pretty hard at removing ambiguity in our editorial conventions through lots of communication. I've still got plenty of master editing to do, but we cranked through an awful lot of pages this way, and the students loved the experience.
Jesse jesse_hurlbut@byu.edu