I'm not sure why, but we decided to use Tumblr for our blog for +Blinkfire Analytics. I think we just wanted to try something different and perhaps a little more modern, but it ended up being a big mistake, so I just finished migrating it back to Blogger.
Tumblr is clearly a great place to run your pornsearchphrase.tumblr.com blog, but not a great place to run a business blog. Search engines don't seem to like it at all, and the inability to add any metadata around your content is a bit crippling. Plus, Tumblr stopped supporting FeedBurner redirects for some reason breaking all sorts of user's feeds and podcasts. Three strikes and you're out.
Luckily, we mapped a custom domain name to the Tumblr, so switching was pretty easy, though a bit roundabout.
1) Turn off the custom domain mapping on tumblr
2) Create an account at wordpress.com and import your tumblr blog
3) Export from Wordpress.com to your desktop.
4) Use the http://wordpress2blogger.appspot.com/ app to convert your export file from #2 to a blogger.xml file
5) import file from #4 to a new blogger blog
6) add the custom domain to the blogger blog
7) change DNS to point your custom domain to blogger
Now, to add some new content there...