What are the calling cards
From Second Life Wiki
In your Second Life, other Residents may give you calling cards. If you have someone's calling card, you can
- easily view their profile from your inventory, by double clicking the card.
- invite them to conferences, by dragging and dropping their card in the IM window.
- view their online/offline status from the cards, in case you got them on your friends list as well.
If you joined Second Life based on a reference link from a Resident already in world, his or her calling card will be the very first one you receive in world. The Resident in question will also receive your calling card by default.
Give someone your Calling Card:
Giving someone your calling card does not automatically result in getting that Residents calling card in return.
By befriending another Resident, the calling cards are automatically exchanged.