Google 9/11 alerts halt

I receive a daily alert from Google for 9/11 news and blog posts. As of May 2, none have been received. Other Google alerts halted the next day.
The Yahoo 9/11 news alerts are still arriving, though we'll know more tomorrow.
The Google alerts had become skimpier and skimpier anyway.
Posts from this blog never made it to the general 9/11 blog alert system (at least not that I saw).
Also, I have run across a number of very embarrassing -- for the feds -- news items that never made it to Google alert status. Also, I can't help thinking that some sources were pruned from the Google system once it was realized that I might be published by those sources.
That is, Google will publish my blog, but otherwise it takes active measures to limit my stuff and either takes or permits active measures to filter what I can see.
This isn't the first time alerts have halted.
In the weeks before 9/11, all Yahoo alerts concerning terrorism, the CIA and national security were blocked. Just froze up. And Yahoo alerts didn't begin again until I said on a journalism listserv that I assumed its alert service was fini. After a hiatus of several years, inexplicably, the alerts started showing up again about a year ago, I'd say.