Twitter tweeted last night that they have expanded their email notification capabilities.
In addition to getting notified of new followers and direct messages, if you so chose, you can now receive notifications when someone you follow retweets you or favorites one of your tweets.
Not mentioned in the tweet are mentions and retweets from people you do not follow. The tweet was very specific, so we can probably assume that these are not included in the new email options.
This may be useful to some users, but my guess is that most regular Twitter users are already using a third-party app that already notifies them real-time of mentions and retweets. If you are already monitoring your Twitter activity and tend to get more than a few retweets daily, these emails may get annoying quickly.
Personally, I used Tweetdeck to monitor my Twitter activity. I turned off email notifications for followers and DMs a long time ago and will do the same for these new options to keep my inbox (relatively) clean. To me, its more spammy than anything else.
What do you think? Useful or annoying?