Well, now we know. Yesterday, the IRS announced that 275,000 US nonprofits have lost their tax exempt status. These nonprofits did not file the legally required paperwork for three consecutive years, and are now considered defunct in the IRS's eyes.
Certainly there has been enough notice, with repeated announcements from the IRS, state nonprofit associations and the nonprofit press and blogosphere, including here. But up until yesterday, we really didn't know how many nonprofits were non-operational, and it was surprising, at least to me, that it was this many. 275,000 represents over 14% of registered nonprofits, a huge number.
Agencies can apply for reinstatement, but few will, I suspect.
Here's the full article from the Chronicle of Philanthropy.