On-Screen Ruler - lightweight, free, semi-transparent ruler
Sirius - An open-source clone of Siri from UMICH
Bluegrams Screen Ruler - A lightweight and configurable ruler tool for Windows Desktop.
Dimension Data - A global systems integrator and managed services provider for hybrid IT.
Pixus - Pixus is an AIR pixel ruler application, a handy tool for web and interface designers.
emailexpert - The all new emailexpert.com for CRM, Marketing & Privacy professionals. The email industries secret resource since 2008 rethought, reworked and relaunched.