I reported this morning at SEW Blog that Google Enhanced Google Alerts & Adds Blog Search Alerts. Yea, so you can now subscribe via email alerts to blog search for specific keywords. They have also updated Google Alerts to "show results from multiple sources (including Google News, the web, and blogs)."
The thing is, there are two cases that I found where people who have subscribed to Google News alerts a while back are now automatically receiving Google Blog Search results.
A WebmasterWorld thread has one person complaining;
My wife runs a local community site that's been in Google News for sometime. To stay up on who’s talking about our area she has Google News Alerts setup using a variety of keywords (her domain, the community name, etc.). The alerts have been in place for over a year and yesterday she started getting notifications that included blogs that are now part of Google News - http://googleblog.blogspot.com/2006/10/on-alert-for-bloggers.html.
The problem is, blog search in general is often not wanted for alerts for many people. So getting these alerts, automatically and without opting in, is bad practice.
Forum discussion at WebmasterWorld.