1. A method comprising: receiving first activity information for a sender of a message sent to at least one recipient by a collection resource at a Web site, wherein the message comprises text associated with the Web site, the collection resource adds a first link to the message, and no personally identifiable information of the sender is collected in collecting the first activity information; storing the first activity information at a storage server; receiving second activity information when a first recipient accesses the first link sent by the sender corresponding to the first activity information stored at the storage server, wherein no personally identifiable information of the first recipient is collected in the second activity information; using at least one processor, using the first activity information to identify a first node in a social graph as being representative of the sender; using the second activity information to identify a second node in the social graph as being representative of the first recipient; determining a category for the first link as a first category type; identifying a first edge between the first and second nodes is representative of the first category type; in the social graph, updating a value of the first edge between the first and second nodes; when the sender sends the message to the first recipient and a second recipient, and the first recipient accesses the first link, updating the value of the first edge between the first and second nodes by a first amount; and when the sender sends the message to only the first recipient and no other recipients, and the first recipient accesses the first link, updating the value of the first edge between the first and second nodes by a second amount, wherein the second amount is greater than the first amount.
1. A method comprising: receiving first activity information for a sender of a message sent to at least one recipient by a collection resource at a Web site, wherein the message comprises text associated with the Web site, the collection resource adds a first link to the message, and no personally identifiable information of the sender is collected in collecting the first activity information; storing the first activity information at a storage server; receiving second activity information when a first recipient accesses the first link sent by the sender corresponding to the first activity information stored at the storage server, wherein no personally identifiable information of the first recipient is collected in the second activity information; using at least one processor, using the first activity information to identify a first node in a social graph as being representative of the sender; using the second activity information to identify a second node in the social graph as being representative of the first recipient; determining a category for the first link as a first category type; identifying a first edge between the first and second nodes is representative of the first category type; in the social graph, updating a value of the first edge between the first and second nodes; when the sender sends the message to the first recipient and a second recipient, and the first recipient accesses the first link, updating the value of the first edge between the first and second nodes by a first amount; and when the sender sends the message to only the first recipient and no other recipients, and the first recipient accesses the first link, updating the value of the first edge between the first and second nodes by a second amount, wherein the second amount is greater than the first amount. 21. The method of claim 1 wherein a personally identifiable information of the sender includes an e-mail address of the sender.