social media convestions and aliens in the ether

Starting locally, I've notice how there are many different conventions about how people use different social media platforms (social networks, email, microblogging, etc) 

At one extreme, some people DM me on slack - this is annoying as, to save my sanity, i have turned off notifications on everything, and I look at different platforms with different frequencies - slack, mostly, once a day, compared to say, whatsapp (and signal and matrix), once an hour at least. While I don't use. teams for messaging, I know people who do, but they are signed on while at work all working hours, so that works ok for them.

At another extreme, some people only use a platform in broadcast mode, so an email list is flooded with "how do I leave this list" messages, or a whatsapp group is flooded with "please stop sending your messages to everyone" messages.

Which leads me to the global problem- without interoperability, we have to select a channel we use for a mode of use, and there are going to be lacunae, or indeed, black holes, and inter-galactic wastelands with no information at all

Which leads me to the universal problem and may be one explaination for Fermi's Paradox - we are hearing from alien's in the ether all the time, but most of them are using broadcast (as are we) and what happens to the shared spectrum when everyone broadcasts all the time? You get a descent into pure noise - indeed, we can work out that lots of alien's are NOT using broadcast otherwise we'd be subject to Olber's paradox, which is to say, the sky would be (modulo quantum limits) white noise from all the interfereing broadcasts. 

A slightly more advanced alien civilisation might think "aha, broadcast - shared spectrum, we need to employ collision detection, or even better, collision avoidance" just like Ethernet and WiFi do already on our planet. However, a little more thought would suggest that the protocol for this might suffer from rather high latency when waiting for a "Clear to Send" response to a "Request to Send" message over the light years.  So obviously smart aliens would do one of three things:

• frequency division multiplexing - each civilisation gets a specific RF band to use
• space or code division multiplexing - we develop really good collimaters or inter-stellar chipping sequences
• cooperative relaying and power management - we place "cell towers" at convenient places (e.g. white holes and black holes) and then avoid interference by switching out of this universe (like cellular switching onto glass fiber networks, but in this case, interstellar wormholes).

The other thing these really smart aliens would do would be to prevent our wildly stupid RF reaching them at all by clever filtering. A "really clever filter" is a very big faraday cage, which could be built out of suitably designed dark matter. This is also why we don' see the white noise - we are in our own RF bubble. We are alone. All the clever people are the other side of the barrier. 

Sometimes they do visit us, but to avoid detection, they largely use obsolete social media platforms like MySpace and Orkut, where they can have a laugh.