Let me pull out quotes from both threads:
Today my site is back at its previous position (2nd)
Well I had a an *old* (1996) site that dropped in serps around the 6th of March (from like first page to page xx). Today is the first day they appear to be coming back.
I saw exactly the opposite - decade old site that ranked decently just disappeared overnight
Seems like mine is back too.... keeping my fingers crossed that it will last a while until next time....
I had a site pop back up today to the #2 spot after totally disappearing for a few months. It's been top 3 for 3+ years before that.
All this type of chatter spiked up on Tuesday, April 10th.
There have been no official confirmations from Google, as far as I know.