Does it work on a Tumblr with more than a few dozen pages?
No, even writing my own, have encountered errors on selected pages where the service simply "errored out" once it reached a certain page.
What other sites?
I have tried Posterous and it failed to import.
Sorry, there needs to be a one-click solution where you request an export (and even if you have to be emailed when it is completed) and a file is generated with your content to download to your computer, be it XML, JSON, or in static HTML.
Well. Guess what? I heard the Tumblr staff is very helpful. Drop them a mail and make sure to include a reference to this thread. Also, specify you want a dump of your data.
I'm sure you'll receive a database dump shortly.
I totally second the founder's missive and this is mine.
Seriously, you probably know how Twitter helps saving lives and is so much better than traditional news and whatnot. Well, during the riots in Thailand last year it was down a good 20% for reading and a good 50% for posting. Do you think anybody cares in Twitter? Ever tried to mail them?
As the old saying goes, you get what you pay for.
Which reminds me of a customer who's asked us to scrap real-time stock data from a free source using demo accounts and then complained because there were downtimes. My answer? Call Reuters and get a quotation.
EDIT: I'd like to state that I always encouraged that customer to get an appropriate account with an appropriate license. This was a 'do it or drop the project' matter (and I wish we had firmer positions in such cases).
And as the response says, there are plenty of other sites that will import Tumblr blogs without a hitch.
Please go away so Tumblr can spend more time/resources fixing problems for the rest of us.