Again, Jeppe nails it in very detailed post: http://www.tigerteam.dk/2014/microservices-its-not-only-the-...
If anyone else finds this, here's a quick thing to paste into the developer console to make it more readable (the content is worth it):
var jq = document.createElement('script');
jq.src = "http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js";
document.getElementsByTagName('head')[0].appendChild(jq);
$("strong").each(function(i,e) {$(e).replaceWith($("<span>" + e.innerHTML + "</span>"))})There's nothing in sending a request and getting a response that's increasing coupling in a traditional sense, and often there's no much of an alternative anyway, if you want donuts, you'll have to request donuts, and then receive donuts.
While I dislike shoving HTTP everywhere for many reasons (reminds me of XML abuse), HTTP is not synchronous, nor asynchronous. It's a protocol sent over a socket. Synchronicity is not the domain of HTTP at all. It's up to the application how it does it.
Additionally, the response can always be a blank acknowledgement of the received request. There are very few cases where you just want to go forward blindly without even receiving an ACK about your request at some level (or alternatively, an error), because sometimes things fail.