There was no need to post this 3 times.
OpenDNS, as the implies, is a DNS based service. That means it knows nothing about URL's, websites, webpages, content, or anything else that is not a DNS lookup of a domain name. And as a DNS based service it cannot give you a comprehensive record of internet activity since it only logs activity if a DNS lookup is necessary. If it's already in a cache somewhere nothing will be sent to OpenDNS. Also, since it's DNS activity it will tell you about all DNS activity, including lookups from applications for anything from reading email that has links in it, to ads on webpages someone is looking at.
The free OpenDNS Home cannot break down activity by individual computer or user. It only tells you about the totality of all activity from your network. However many devices that is will depend on how you have configured OpenDNS on your network.
If you want to break down DNS activity by machine or user you'll need to use one of the pay services that uses an agent or an in-network virtual machine that can differentiate that kind of additional information.
