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I think His Majesty makes *the* point about this question.
And continuing the analogy, you can either pick it up at your favorite news stand (browser), read it at your favorite hang out (FB, G+, here), or have it delivered to your door (subscribe). <<
No one way is going to be 100% effective and PART of the responsibility is on the audience (you have to make the effort to be available on an e-mail list or subscription or paper mailing or group). The only way to be sure that you're covering all your bases and reaching the widest possible audience (you'll still never reach everyone) is to hit all the various outlets. Granted, that's hard to to do when you've got updates a week out (i.e. The Mews can't be updated a week out), but then make sure you include a valid website with up to date information within your Mews flier.
When I was event steward with Mistress Nikolena for Gryphon's Fest a few years ago, we made the conscious decision that we wanted to reach as many people as possible. Which resulted in the creation of a 'Communications' spreadsheet and planning for 8 months. We listed all the various Facebook groups, personal pages, G+, e-mail lists, events attending, newsletters, and even hand-written invitations. We split it up between the two of us and every time something was updated or new announcement made - we distributed to as many as possible (with the understanding that written invitations couldn't be updated, but we had included our website within, which was updated almost daily) and we made a note that we'd done so on the spreadsheet. I'm sure some people got tired of seeing the multiple cross-postings, but it was really the only way to make sure the info got out to as many people as possible. As a result, we had almost record attendance at the event.
tldr; Empirical data of Facebook vs E-mail List vs Print-out is only relevant if your goal is to only reach one of those groups. If your goal is to reach the widest possible audience - then you need to cater to all the groups, as there are most certainly people within each that ONLY use the one form of communication.