Tumblr's reblog feature enables bloggers to engage in an ongoing conversation by reposting each others' content and adding their own comments. Each time a user reblogs a post, Tumblr formats it with indentations by inserting the content within "blockquote" tags. When a post has been reblogged repeatedly with several users adding their comments to each reblog, each separate comment appears in indented clusters beneath the original.

Reblogging

When you reblog content from another user's blog, Tumblr formats the original content using the "</blockquote>" and "</blockquote>" tags in your post, with the original poster's username as a hyperlinked source. Tumblr publishes the comments and media you add in the post-editing form without any formatting or indentation, signifying that yours is the latest comment in the conversation. You can reblog conversations with more than one participant, or reblog another person's reblogged post and comments.

Clustered Posts

If the content is a comment on a reblogged post, each user's post displays as a block quote with the hyperlinked source attribution to each username, so that the separate posts appear clustered or nested within each other. It may be challenging to identify the username associated with each nested comment, particularly in longer conversations, but you can follow the vertical line that displays directly to the left margin of each post to the original poster's username.

Finding Original Sources

When you reblog a nested conversation, your post displays all the block quotes from all the users that have added content to the post. If you only want to reblog the original post and not the nested conversation, click the username of the comment you want to reblog to visit the original post's permalink, and then click the "Reblog" button in the Tumblr menu on the page.

Reformatting Nested Posts

By default, Tumblr formats nested posts by embedding "<blockquote>" and "</blockquote>" tags for each added reblogged comment. To format your post another way and remove these tags, highlight the text, and then click the "Block Quote" button with the vertical line and right arrow in the formatting menu. If the content is within a nested post, it may be embedded within several tags. If so, you may have to repeat these steps several times for the same text to remove the indentation and formatting entirely. You can also click the "HTML" button in the formatting menu to remove the "<blockquote>" and "</blockquote>" tags manually.