Userscripts.org

Mimics a "Compact" density setting for Google Contacts (until it is implemented natively by Google)

Make Yahoo compact and with ads where they belong [DEAD]

Show/hide the header, footer and sidebar tabs on iGoogle to save space! Perfect for small screens or netbooks!

Removes the top bars in Google Reader to make more room for your feed reading.

Includes features of multiple scripts that help to make google reader faster and better.

More compact design for the new Google Reader with Google+ Integration

This CSS tweak will make Google Reader's new look more compact and less depressing by adding some eye-friendly green colors. Inspired by lipsumar's "Google Reader compact" and Green Sky GMail theme.

Improvements for e-shuushuu: Sidebar by default is hidden; Images are zoomable; Replies are hidden, but can be shown; Search now is in pop-up.

my personal version...for my girlfriend :P very minimalistic... wallpaper from interfacelift (see source) oh...and disable suggest...in preferences...

This maximizes the vertical real estate in GMail by collapsing the links on the left to an image box, and moving the search to left side (This is a modified version of Pavel Gutin's original Gmail Compactor).