Ember services used with observers

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  myService: Ember.inject.service("my-service"),
  actions: {
  	increaseProperty: function() {
      this.set("myService.someProperty", this.get("myService.someProperty") + 1);
    }
	}
});

application.template.hbs

<button {{action 'increaseProperty'}}>Increase service property</button>
{{my-component1}}
{{my-component2}}

my-component1.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  myService: Ember.inject.service("my-service"),
  hasChanged: false,
  onChange: function() {
    this.set("hasChanged", true);
  }.observes("myService.someProperty")
});

my-component1.template.hbs

Component 1: Service property has changed: {{hasChanged}}

my-component2.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  myService: Ember.inject.service("my-service"),
  hasChanged: false,
  onChange: function() {
    this.set("hasChanged", true);
  }.observes("myService.someProperty")
});

my-component2.template.hbs

Component 2: Service property value: {{myService.someProperty}}
<br>
Component 2: Service property has changed: {{hasChanged}}

my-service.service.js

import Ember from 'ember';

export default Ember.Service.extend({
  someProperty: 1
});

twiddle.json

{
  "version": "0.4.16",
  "EmberENV": {
    "FEATURES": {}
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.1.0",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.1.0/ember-data.js",
    "ember-template-compiler": "2.1.0"
  }
}