Valve keeping up with the trend of "worst kept secrets". You need an invite to join the alpha but since everyone who owns it can refer their friends, it spread very quickly.
I've been playing it the past few days and it's honestly very fun. Still a bit rough around the edges (especially in terms of balance) since it's in early access, but it has serious potential to be dota 2 levels of popular.
For the unaware, Deadlock is a 3rd person shooter MOBA. It feels like a mix of Dota and Overwatch/Team Fortress. Nobody is allowed to share footage or screenshots, but obviously with so many playing there's a ton of leaks out there.
I remember playing Dota 1 and 2 in parallel for a while because so few heroes were in the beta and I wanted to play new hotness like Ember Spirit. Fun times.
Quitting Dota has been great for my mental health, though. But I guess I'm at least curious enough about what the frog is cooking to risk getting addicted to something new.