There exists a wordpress setup, having a closed user group (ie one cannot produce a login for themself). Whenever I write your blog &lifier surveys are published into it, I recieve up-to-date over mail. But, how you can make certain to update other customers also.

The main one I have tried personally is Subscribe to Comments and contains labored great. Others include Subscribe to Comments Now! and also the one Chet pointed out, Subscribe2. Subscribe2 appears to achieve the best admin interface from the three, I believe I would try that certain.

I'd consider using a Wordpress subscription wordpress plugin. The renowned wordpress plugin with this is known as Subscribe2. It works best for registered customers. Otherwise, browse Wordpress's Extend page for the same one. I guess fixing your condition such as this does not allow it to be a programming problem, why re-write code?