After creating a map in ArcGIS for Desktop or in ArcGIS Online, you can share it in different ways. One of these sharing options, is to create a web app. You can choose different templates and add more options to this web app. For example: you could add the option ‘print’, which means that the viewers of your web app can print your map. It’s totally up to you to determine what external users can or can’t do with your map. Here you can find an example of a web app: http://gis.irisnet.be/bruciel/#You can localize important sites in Brussels and compare them over time – this was one of the options that was added by the creator of this web app.
