If you want to know how the FBI were able to identify people quickly and set up no-fly lists, then the screenshot in
will enlighten you.
The TL/DR version is that a Parler press release accidentally revealed information that hackers needed to create accounts without verifying an email address. This allowed them to use the "forgot my password" feature to gain access to administrator
accounts, and that allowed them to create millions of new administrator
accounts to ensure they weren't locked out.
Then then used those administrator accounts to download everything via crowdsourcing processing power, and that "everything" includes not only posts which were deleted in the wake of the insurrection, but also the details of the "verified citizens" on Parler - a status you get by uploading a picture of the front and the back of your driver's license.
As to that latter, BTW, this isn't in the tweet, but did you know that Parler is founded and funded by Rebekah Mercer? The same Rebekah Mercer who funded and was an executive of Cambridge Analytica and is now funding and an executive of the company that rose from CA's ashes, Emerdata?