Partsbox.io is a new service by Jan Rychter, that aims at keeping track and managing your parts in your inventory or workbench. You can do quick searches, link datasheets and add notes to parts. There is also a planned social layer which allows users to request and share your parts to other makers. The service is free for Makers for 2000 distinct parts and 400 storage locations.
Jan is very receptive to suggestions. Make sure to let him know if you have any. Also, Vinicius.jlantunes, a member at 43oh, has posted a detailed review of the service and how he uses it.