So you want to organize an Internet Yami-Ichi
yami-ichi.biz
yami-ichi.biz
These already exist, or existed: There's the pirate bay for piracy, and the various incantations of The Silk Road. These also attract a lot of attention and get shut down; so they need to operate in a weird "word of mouth" way where only the people who look for them find out about them.
Perhaps consider the term "flea market" or "art fair" instead? It implies legal goods sold by independent vendors; with little overhead from the venue.
Where I live, (Northeastern US) there are art fairs all over the place during the summer. They travel from park to park, every weekend showing up in a different place; and they look just like what's in the video. (Except they don't have the requirement that everything has to have something to do with the internet.)
So, you could define it an "internet art fair" and everyone would know exactly what you're talking about.
"Internet Flea Market" sounds pretty great actually! :-)
Cheers