OpenDNS is a DNS based system, and as such knows nothing about URL's (or anything else) that are visited. It only knows about domain name requests that it receives from your network.
When you are looking at your stats you can sort by various things, including what is blocked. If you click on a blocked domain it will tell you "why" a particular domain was blocked, generally because the domain belongs to a category that you want blocked
You can also look up individual domains in the domain tagging section of this website https://community.opendns.com/domaintagging/ That particular domain you listed is not currently categorized, but the parent domain is currently being voted on https://domain.opendns.com/ggpht.com?__utma=120785690.151338177.1421455055.1440985361.1441601680.27&__utmb=120785690.4.10.1441601680&__utmc=120785690&__utmx=-&__utmz=120785690.1421455055.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__ut... It doesn't appear to be any sort of porn site, but more than likely is a domain used for advertising purposes, or perhaps malware
Just remember, just because you see a domain listed in your stats does not mean that anyone visited any particular website. It could just as easily be a domain that is used for resources on a webpage or something else
Also, if you are worried about your kids or someone else going to websites you don't want them going to, you need to make sure that they are actually using OpenDNS on all of their devices and aren't instead using a different DNS service. There are many ways to do that, but one of the most important methods is to remove administrator level rights on those devices so they can't change settings you don't want changed.
