I'm still not using the Tumblr much, but I do go poke at it from time to time to see what's there, and it does have some nifty features. It also has a bookmarklet that you can use; click it on any page you want, and it pops up a "post this to Tumblr" box that lets you post the link, some text, a picture, whatever you want. (That's how I managed to post the White Collar picture I have up.)

I just tried to share a post with you on G+ and it's not letting me. *kicks it* Maybe they figured out people were using it for invitations to a wider degree than they were expecting. It's not letting me save any email addy in the "share with" field, not even a gmail addy. Bah.

I'll try again in a day or so, though!