..ah, those "gravatars", right.. forgot about them.
Ghostery blocks them, so that text is displayed instead.
Surprised this is capable of breaking in the actual post though like in the example above!
On Chrome and Windows 7 (and I think, but not 100% sure, on Chromebook) Ghostery just blocks them with no placeholder text. I have gravatar set on block.
It might have been because I had one of the generic snowflake-y avatars before.