In an ideal situation I'd imagine something like this:
On a player's profile, you can subscribe to their calendar events. For example, I'm creating a series of tournaments that start on specific dates. I'd then add those to the calendar and only people who have subscribed to mine will see those dates in theirs. That way you can follow specific events. Think of AWP, Clan League divisions, Berlin Open, Seasonal starts and finishes, Map of the Week, etcetera. And maybe add a notification for some things. I rarely check out the blog for Warzone for example, but if I'd follow Fizzer and he updated the calendar as soon as he made a post and I got a notification, I'd probably go check it out.
Also, Lionheart asked me to post this concept picture: