I saw that someone already explained that Tumblr has an auto-queue feature, but I haven't seen anyone explain why it exists, so I'll explain why. One reason is that it's part of Tumblr etiquette to use it--it's considered rude to post a ton of stuff in real-time, because your friends will have to scroll and scroll and scroll to see any of their other friends posts on their dashboard. If you sit and tumble for an hour or two, it's really easy to post a MASSIVE amount of stuff. Reblogging takes only a second, and original posts can be made pretty quickly, especially if you use a Tumblr extension on your browser.
Another reason is that it keeps your Tumblr consistently active. If you post in real-time, only your friends who are only at the same time (and shortly afterward) will ever see your posts. I've got a few hundred people following me and vice versa--people follow each other MUCH easier than on a site like Facebook. (I think it's because Tumblr is less personal and more anonymous than Facebook. It's more like the web used to be.). I can't possibly see everything my friends post, but I'm more likely to see a particular person's post if they auto-queue. Here's Tumblr's explanation--they might explain it better than me:
http://www.tumblr.com/docs/en/advanced_post_options#queue
The hermit makes sense to me--it's how she thought of herself. Despite her friendliness, she writes a lot about feelings of isolation.