I've been trying out several different offline blogging tools, things I've always shied away from because of my obsession with getting valid XHTML. But I do spend a fair amount of time on the train and despite the advantages of a 3G card in this laptop, doing the kind of research and basic fact checking that I normally do for a post isn't really viable in that environment. So I've been looking for something that lets me write stuff and hold it offline until I have the connectivity I need to finish it off.
Hence, I'm now using performancing for Firefox, which so far seems pretty slick. It has a "save as note" feature which seems to meet my offline requirements. I tried out Deepest Sender, another Firefox extension, but there seemed to be no way to manage seperate Moveable Type blogs on the same host which is now essential with the launch of a new Talis blog called Nodalities.
It seems that Firefox/Mozilla as an application development platform is just becoming mature. Certainly extensions such as performancing seem to work well and can take advantage of all the web goodness that Firefox offers, plus they're automatically cross platform. I expect to see many more similar applications in the coming months.