What is this tab and how do I get on it?

I don’t know how long it’s been there though, lol :-)
I see some memes with a lot of views, but no upvotes. I also see some newer ones that are still on the first couple pages. Not exactly sure what makes them viral. Maybe they are ones that have been shared outside of the imgflip site.

Seems like the criteria to get on are a combination of the number of views and how new it is. Hasn't updated all day, maybe the viral pages get sorted once a day. If that's the case, the viral pages will likely get shuffled at midnight PDT (same time you get your new submissions)

This is now (Jan 4, 2018) on page 9 of viral.