This has been happening since at least last night. The little wheel just keeps spinning round and round. I notice that flags and microbadges aren't displaying info when moused-over (mouse-overed?) which seems related. Some of the culprits:
pixel.quantserve.com images-geekdo.com i2.yming.com (not sure I spelled this one right as I've only seen it once)
Also, this may be related, may not ... the little icon for "next" subscription isn't showing, only reads "no subs".