My Mark all as read button was missing on the laptop in google reader this morning, and some other things didn’t look quite right (the google reader logo at the top left was missing for example). I tried messing around with greasemonkey and disabling the better greader extension and narrowed it down to something within greader. I then checked the skins option and noticed that it was setup to use the optimized theme. I switched the skin to none, pressed F5 to refresh and all my buttons reappeared and the other sections of the screen didn’t disappear either. Now I can mark my folders as read again and get my count back down to a reasonable number.
Having said that, it doesn’t look that malicious – you would have to be tricked into entering data into one page, which can then be sent to the malicious site at the same time, so you are probably only at risk if you do random surfing or surf in dodgy web site areas in the first place – and if you are doing that then I really hope you are not running internet explorer (or as an admin!)
From Rhyley.org are some more flickr greasemonkey scripts. I’ve added flickrPhotoPageEnhancer.user.js and FlickrThumbnailsEnhancer.user.js
Note that you will need to edit these scripts (and others) to include the www*.flickr domains as flickr have broken a lot of scripts by hosting some pages at www-us.flickr.com after their servers were moved.