Functionality is the use of technology on the site. Good functionality means the site works well. It loads quickly, has live links, and any new technology used is functional and relevant for the intended audience.
It has impact without being over-dramatic and itloads really quickly, especially the video on the opening page, which is well worth a look for any teenager who is new to online communities.
Itloads much more quickly than the old iOS Google Maps app because it uses vector graphics instead of bitmap graphics, and it has turn-by-turn navigation which the old iOS Google Maps app did not have.