Trek is both a Web browser and a new kind of social network. It allows its users to meet and interact by overlaying the Web with graphical avatars. Said avatars represent each user on a given page and can be moved freely about the content. Users can form parties or "browsing treks" and move about the Web in a group.
Libravatar is software that allows domain owners to control how avatars (profile pictures) are served to other Web sites. It implements a modified version of the Gravatar API, adding a few features such as federation, LDAP authentication, and OpenID support. Libravatar powers libravatar.org.