One little (but amazing) feature on FFFFOUND that I have grown to love and depend on are the keyboard shortcuts for navigating to the next/previous image and page. You can see the shortcuts in the upper right corner of the page when you visit FFFFOUND.
In short, press 'j' to move to the next image, and when you reach the last image of the page 'j' moves you on to the next. It's awesome, and I've found myself repeatedly pressing 'j' when reading random blogs. And it doesn't work. And I become very sad.
It might be that FFFFOUND isn't the first website to do this, but it's the first time I've come across this particular shortcut. And everyone needs to adopt it, because it's so freaken' great.