Tumblr's content attribution fix

Starting today, reblogging will no longer insert attribution into the content/caption of the post except to quote content added by the parent post.

[…] This feature has an even bigger win: When creating a post, you can now attribute its content (eg. a pull quote or image) to a source outside of Tumblr. That source gets clearly attributed everywhere that post is reblogged on Tumblr.

Excellent news.