I don't know if there is a problem. I have three Alerts set up and I get 2 to 3 e-mails every day with Alert messages. It has been working fine for me.
I'm not sure what the Twitter relationship had to do with Alerts. The Alerts that I receive have never been tweeted. I have always thought that it was indexing that triggered an Alert.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin