Tumblr reblog with an x?

[Grace]

On tumblr, sometimes when people reblog something and add text to it, the next person to reblog just puts 'X'. What does this mean? Why do people do it? I've been on tumblr for over a year and still have no idea. Thanks.

[Savvy Nerd ☁]

Usually that X is a link to another blog, either the original post's creator or their own blog, or the source. People sometimes also do it just to have their blog name as a comment on said post.

[xoxo-gossip-girl]

they don't want to write anything, but they still want people to view/check out their blog, so they comment that x (and it makes you redirect to their tumblr when you click it)