Now I'm posting more on Dreamwidth, I want a way to keep an offline copy of everything I've written here. (I am almost hoarder-like in my desire to keep copies of everything I’ve written.)
Hooray for sites with sensible APIs! Dreamwidth has an XML-RPC API, so I've written a short script that grabs a copy of all my posts. It saves a JSON file with all the data from the API, and an HTML file for convenience (and grep).
If Python is your thing and you'd find it useful (or just want another example of using the Dreamwidth API), code is on GitHub:
(Usage instructions in the docstring; whole repo is MIT.)