Methods and apparatus to monitor online activity

An apparatus to monitor online activity, the apparatus comprising:

• a first data structure to store, at a first server, first uniform resource locators received at the first server via first network communications from a first client device, the first client device having a meter;
• a second data structure to store, at the first server or a second server, second uniform resource locators received at the first server or the second server via second network communications from a second client device, the second client device not having a meter;
• and
• a processor programmed to:
• determine that ones of the second uniform resource locators from the second client device correspond to online activity of a user associated with the first client device based on ones of the first uniform resource locators matching at least portions of the ones of the second uniform resource locators;
• and
• in response to determining ones of the second uniform resource locators from the second client device correspond to the online activity of the user associated with the first client device, associate the second client device with the user of the first client device, the associating including setting a cookie associated with the user on the second client device;
• associate third uniform resource locators from the second client device with the online activity of the user associated with the first client device based on the cookie set on the second client device;
• and
• use the third uniform resource locators to identify subsequent online activity of the user at the second client device after deletion of the cookie from the second client device.

A tangible computer readable storage medium comprising instructions that, when executed, cause a machine to at least:

• collect first uniform resource locators from a first client device, the first client device having a meter;
• collect second uniform resource locators from a second client device, the second client device not having a meter;
• determine that ones of the second uniform resource locators from the second client device correspond to online activity of a user associated with the first client device based on ones of the first uniform resource locators matching at least portions of the ones of the second uniform resource locators;
• in response to determining ones of the second uniform resource locators from the second client device correspond to the online activity of the user associated with the first client device, associate the second client device with the user of the first client device, the associating including setting a cookie associated with the user on the second client device;
• after setting the cookie on the second client device, associate third uniform resource locators from the second client device with the online activity of the user associated with the first client device;
• and
• after deletion of the cookie from the second client device, use the third uniform resource locators to identify subsequent online activity of the user at the second client device.