Thanks so much to Amy Sample Ward for blogging about Posterous! Just email them content and they post it for you. Woah.
This is exactly the kind of tool I should have used back when I started a blog without home internet. There’s no process for signing up, you don’t have to do any account managing or appearance adjusting if you don’t want to, and they embed your media for you. Yes, this helps people who aren’t familiar with much web technology beyond email. It also reduces time commitment for anybody, no matter how tech-savvy.
It was a piece of excellent timing, because we were just brainstorming at work about some low-cost, low-time-investment ways to improve (specifically Web 2.0-ize) our website as we bide our time till a major overhaul. Posterous would be a great way to post our informational emails as a blog; this would make them accessible to people who don’t want more email and also put them in a format that welcomes comments and discussion. The best thing about this is we can just add post@posterous.com to our mailing list and it will post automatically. Very exciting for a bunch of efficient nonprofiters!
I tested out my own just now. The chief lessons I learned are that it is instant, the default style is clean white with orange links, you can BCC them, and that you should send photos as attachments rather than as links. Things to explore: getting a better URL, changing the title, adjusting the look.
What do you think? Who is this useful for?
Learning to Teach English 
Hey Emily! Great thoughts! I think that the biggest initial draw for Posterous is that it can be a huge catalyst in converting non-technical, non-social media-favoring folks into adopting new tools, like blogging. Email is inescapable at this day and age, so, why not use it in another way – you don’t even have to learn anything! (Though, that’s a stretch for me since I’m such a learning person, but hey, not everyone is like me!)
Amy – it’s also difficult for me to relate to not wanting to learn a new tool, but you’re right, social media is for everyone, not just me!
Re: email is inescapable, this article from the NY Times might interest you – this IBM employee says he escaped from it! http://www.nytimes.com/2008/06/29/jobs/29pre.html