Daily update notification or sth?

Hi there,
My problem is, that I’d need a plugin that would allow to send a daily email with information about global changes on site to the admin (or not only). By that I mean posts added and modified, new users etc.

And another one that allows to send a notification to a GROUP of users (i.e. that liked the post) when the posts custom field changed.

I’m searching the internet and forum from couple of days now and can’t biite it any way… So I am hoping that maybe someone from here could help me find what I need, or instruct me to find the right way to achieve my goals.