Comcast subsidiary Plaxo.com is now going to focus purely on address book maintenance. That was the original company direction, but it wandered into social networking features for a while after launching Plaxo Pulse.
Plaxo.com was co-founded by Sean Parker, the entrepreneur portrayed by Justin Timberlake in The Social Network movie. The idea behind Plaxo is for everyone to create an account with up-to-date contact information. As people make more connections, their network will grow.
Plaxo is also launching a new service called Plaxo Personal Assistant, which returns checks public data to notify users when their contact information has been changed. Other Plaxo services include Plaxo Basic, Plaxo De-Duper, and Plaxo Platinum Sync (paid).