That's an interesting request and one that I think makes sense.

Short answer is: there is no way to do this right now - other than your users subscribing to the rss feed that is.

What I think would be a good idea is a "subscription" based system, where users can elect to receive notifications when a new blog is posted. Just sending email to everyone is considered SPAM and not something I would do by default on the blog.

What do you think?

This is right for public blogs (and forums, repositories, etc.), although in a corporate environment the administrator needs the ability to subscribe users to a module so that necessary corporate/project messages can be transmitted. So I would promote the inclusion of this feature, alongside the ability for users to deliberately subscribe/unsubscribe.

An example is Discussion Forums that I set up on a client project by project basis in the delivery of our consulting services - I need to be able to subscribe project members (inc clients who login) to their specific forum (and for them not to be able to access other clients' forums for obvious confidentiality reasons).

As it happens I discovered to my horror that I couldn't isolate forums from each other using the current core forum module, so had to buy and install ActiveForum (3.6) to get around that - but with AF the admin cannot subscribe users to forums! Anyway that's a different issue, which also may be relevant to blogs, but the point remains that admins really do need the ability to subscribe users to modules like this.