You just need to sign up for a free account and create your profile.  Anytime you network, you send a text message to Contxt’s system with your contact’s 10-digit id, and both his contact details will be saved in your list.  You could access contacts from your phone by accessing the system’s “digital rolodex”.  Think about it, no need to worry if you are changing phones/jobs/addresses, since your new data shows up in your contacts’ accounts automatically.

The service is being offered in the US via SMS, but I’m sure it’s a matter of time before they go global via mobile internet.