GPT-4 is out. There's also a LessWrong post on this with some a lot of discussion. The developers are doing a live-stream ~now (yesterday).
And it's been confirmed that Bing runs on GPT-4.
Also:
Here's an image from the OpenAI blog post about GPT-4:
(This is a short post.)
Naively, maybe they each thought Pi day (March 14th) would get them more attention? I'd guess it's most likely a coincidence given how many big releases there have been recently, but would be amusing if it was Pi day related.