Given that essentially every American in the country interacts with USPS tangentially every day except Sundays, it seems reasonable. I get an email every day with an image of all mail coming to my mailbox, that probably counts when I open up the mail.

This is a wonderful service. I did it when I moved and set up forwarding, but continue see it every morning.

USPS Informed Delivery / Daily Digest is awesome and underappreciated

And is one of the few remaining [government] things that fails (for me, at least) to auto-verify for those of us who have an apostrophe (or suffix) in our name. I keep meaning to get signed up but, like the TSA quick-pass programs, it's always low on my list and I never get around to going in to "verify my identity". The auto-verify fails with any/all cards I've tried tried to use all the auto methods they provide (and address is owned & occupied single-family home/very 'standard').

Anyone that works on this -- please try to recognize those of us with "unusual" characters or a suffix as our given name! =D

Meanwhile, chilling effect - government knows who sends you mail and can actively build a list of whom sends you mail and whom you send mail too.

The government has known this as part of the covers program ever since the 2000s (or before). Informed delivery is just letting people do something useful with that information, which is a welcome change from other nasty surveillance programs.

We’ve gotten USPS mail on Sundays for awhile now. Why? I don’t know.

There used to be half a dozen or so cities that did Sunday mail in lieu of Saturday, typically in areas with a high Seventh Day Adventist population. However I think most of them have since moved to do Saturday delivery instead

It's mostly people tracking their online shopping. Most small, lightweight packages that aren't delivered by Amazon are delivered by USPS. Lots of stores/receipts will link directly to the package's tracking page on USPS's site.