One of the frustrations of blogging used to be the challenge of knowing when someone had responded to your post. Trackback tried to make it possible to see when someone wrote a blog post that cited yours. Disqus tried to let you know when someone mentioned your blog in comments on another. But neither became universal enough to really work.
Nowadays within Facebook it is easy to tag someone in an update or comment (and this is partly what makes the energy flow better in Facebook) but it is just within Facebook. The @ sign in Twitter and the + sign in Google+ help too but again these really only work within their own environments. If, like me, you post blog posts in various places the conversation stays fragmented and the crossovers between the members of your networks is limited.
Writing a blog post, wherever you do it, is like lobbing pebbles into a pond. You get better at creating ripples. The trouble is that at the moment you end up lobbing many pebbles into many ponds.