Wordpress.com's Follow and Like - Anyone Thought of This as a Plugin?

Not sure if this is something that Wordpress will release, but I see they have a really cool feature to follow and like blogs within the network and get email subscriptions from that particular blog.

You can read more about this feature here.

I can see this as a super powerful feature for those who want to focus more on blog content vs a social network extension like Buddypress does.

What's the thoughts on developing a plugin that can do this across a blog network? Has anyone thought of this (the community here or staff) or know of something similar available?

Would appreciate some feedback on this one