Reporting on "activities" from timeline feature

Very excited about the upcoming "timeline" feature. 

A challenge I've heard many customers talking about before is getting a sense of which of their customers have they engaged recently. 

My idea/question is: would the activities in the "timeline" view be reportable? E.g. would I be able to write a rule / report to show all accounts that don't have activities logged in the last X days? 

I think this will be a very strong feature that many customers are going to be interested in.