Welcome to Web Applications at Open Source Law
Over a year ago I complained about the poor markup facilities available within OpenOffice. A couple of people suggested some options, including things like wdiff. While they performed pretty well, they were a bit of a hassle to work around with, including having to drop to a command line and run a number of commands in order to do a markup. Moreover, the markup was easily fooled with some minor changes.
Some other people suggested I do it myself, so I did, including teaching myself Python along the way. This website has a working prototype of the application running. This is for limited testing purposes.
Some things to note: performance is ok for short texts, but can get quite long for long texts. Performance tuning is on the agenda.
Please lodge bugs with the bug tracker: http://apps.opensourcelaw.biz/trac/newticket. Other issues can be emailed to bugs at apps opensourcelaw biz.