This is my system for archiving and organizing all my Tumblr posts offline. (It could also be used for Facebook, or LJ or any other site that allows you to pull an RSS feed).
Evernote is organizational software I’ve been using for several years, and I love it with the fiery passion of 10,000 suns. It keeps pretty much my entire life organized, with the exception of my calendar. It’s a program for storing documents and files of just about any type, and it allows you to organize them into notebooks (of your designation), and to tag them any way you like. Many types of documents are also text searchable. It is phenomenal. Really. (There are also some other amazing features, like a web clipper that is possibly the best thing on the whole planet, and it’s word processor is good enough that I do all my fiction writing in Evernote, as it’s really easy to organize chapters).
In order to get archive/backup/offline copies of all your future Tumblr posts, first you’ll need to find your Evernote email address. You should be able to find it under “Account Summary,” and it will end in “evernote.com.”
Next, go to Blogtrottr.com, and create a free account there USING THIS EVERNOTE ADDRESS. That part is important. 😀 (Unless you want to bypass Evernote, and just send your posts to your email account. If you have a fab system for organizing emails, this might work, and you wouldn’t need Evernote. But Evernote is wonderful and you want it anyway, so pretend I never said this about emails :D).
Now, in Blogtrottr, just subscribe to the RSS feed.
That’s really all there is to it! Now, all posts that you make will be sent directly into Evernote, where they will be kept on the Evernote servers, and also synced to your harddrive (you can control how often this happens; I have mine set to sync every 15 minutes). Once they’re in Evernote (I have them all dumped into a folder called “Inbox”), you can go in and tag them and organize them to your heart’s content. And edit them. And all hyperlinks and images will be included. (Although sadly, tags are NOT).
Now, like I said, this is only going to work from posts for here on out, but I wouldn’t be surprised if there is some way to pull all your Tumblr posts relatively easily. Tumblr doesn’t have an export feature, to my knowledge, but something like Tumblr2WordPress might be useful? Especially if maybe you actually imported them into a new WP blog that was set up to send posts to Evernote. (You can set up multiple feeds in Blogtrottr).
So, hopefully this helps, and let me know if you have any questions. 🙂
ETA: A couple of things to add – you’ll want to select “Realtime Push” rather than any of the digest settings, so the posts come individually. Also, under email preferences, I have them: “Enabled,” “Show Thumbnails in emails” and “List media files (enclosures) in emails.” And Mail format is: Multipart text/html.