A manufacturer's datasheet is the primary source of info for most parts. Physical measurements like length, width, height, pitch are almost always listed along with a dimensional CAD drawing of the part. Electrical specifications describe the voltage and power a part is rated to handle so you know if it meets your needs. More complicated parts like chips also have detailed information about the function of each pin, and how the chip works.
The OOMP part page, part number, and back label give the most common characteristics of each part so you don't need to dig through the datasheet.
Bonus tip: when someone writes RTFM in a forum post it means Read The Fine Manual. Most questions are answered in the datasheet.
An XML data file that describes each part is also linked in the datasheet section. This file, in the OOMP XML descriptor format, contains all the information we use to build the part webpage. We hope it will be useful for part management software, cool web applications, and other special sauce.
Making CAD footprints for a new part takes a lot of time. Each part in the OOMP library has a professionally designed schematic symbol and PCB footprint, ready to use on your next circuit board layout. Footprints are available for KiCAD and Cadsoft Eagle, with more on the way.
Footprints are public domain (CC 0), (ab)use the libraries however you want!
Breadboard and schematic diagrams are 2D models of parts you can use to make clear how-tos or kit instructions. Open the part diagram in your favorite graphics editor and drop it on a bread board to show exactly how to recreate your project.
Vector source files (CDR) can be edited in Corel Drawl, simple image files (PNG) and Adobe Acrobat (PDF) versions also available.
At heart, OOMP is a time saving and part organization concept. The label on each part packet is designed to give the essential information without digging through a datasheet. Uniform part numbering makes it easier to organize parts and find what you need at a glance.
Front (retail), back (specification), and bulk packaging (inventory) labels are in the InkScape SVG vector format.