I think it's a list of all clients they have had since starting the company to include smaller scale events. If you look at some of their older videos on Vimeo you can see some of the events with those clients. Maybe not everyone but I doubt they can lie on an official business website. Thats just asking for a lawsuit if they add names they have not worked with.
It should probably say, "Past Clients." I wish they would have taken one of those "hundreds of hours" and made it so the "Follow Us" links on the homepage went to active XA accounts instead of the "Wix" pages. Granted, Wix is more active.
$CMGO #XA
ETA: Don't try the site on a phone. Very unresponsive.