If you want to spread the word far and wide, Tumblr is a great resource.
If you want to send content from one blog to another, though, Tumblr isn't so great, as they recently turned off RSS importing. You can circumvent that restriction with TumblRSS as long as you're willing to set up a Webapp and restrain yourself from posting more than 100 items per day. Here's how to do it:
- Log on to your Tumblr account.
- Go to the tumblRSS page and click "Login."
- Click "Allow."
- Click "Get Started."
- Enter an e-mail address. (It doesn't have to be the same one you use for Tumblr.)
- Enter a feed URL (this can usually be found on the site you want to import--look for the orange and white icon), select which Tumblr blog to import to, select post type, then click "Submit."
- You can add more feeds if you like, but remember that you've got a hard limit of 100 posts per day or TumblRSS will be permanently blocked.
That's it! One caveat: TumblRSS doesn't dig deeply into your archives; only the most recent post gets imported when you start. After that, every new post goes up on Tumblr.
Thanks to MakeUseOf for the link!