I've been using Farcaster since @dwr onboarded me back in Fall 2021. I was very pleasantly surprised to see the bump in DAUs / interest once frames were launched. 

That being said - Why did frames make Farcaster pop? Did Farcaster just reach critical mass already and this was a catalyst? Or were Frames the kind of ...

... innovation that was just not possible on social media beforehand?

Both answers feel inadequate. Farcaster has been attracting retentive users for a while. And Facebook invented the OpenGraph tags that enabled Frames!

Cat that makes Dune dashboards. 🇲🇾
Building /phi @phi island!
φ Community & Data Lead.

Wasn't it open before? Or do you mean that it stopped being invite only?

it wasn't Frames, it was it opening for US market. Frames was at the right place at the right time.