In Moodle (2.4) it is possible to generate a URL for a calendar so it can be synchronized with other systems, such as Google Calendar. This approach, however, is limited because the perspective of the Moodle calendar is that of the user who generates the URL.
For example, if I'm enrolled in three courses, and I generate a URL, it is the calendar of those three courses (or whatever I'm enrolled in) that will be synchronized with the external system.
My university as well as many other use platforms such as Google Apps for Education, whose Calendars allows creating a public calendar that is linked to a URL for a iCal file.
For these environments and others, I'm suggesting that Moodle provide a URL to a single course's calendar only, such that individual Moodle course calendars can be integrated with Google and other web calendar platforms. There's an argument to have public views of calendars for courses, as opposed to exporting individual users' calendars.
The current URL generated has an authentication token in it, which is why I indicated "could be a security issue" below. I think Moodle should probably have a configuration of whether or not a course calendar is public/private, much like Google does with its calendars. I see the current URL generation as a kind of quick fix, but which doesn't measure up to web 2.x, in my opinion. Google and other platforms have awesome calendar support and huge resources to develop those features. Moodle should focus on its strengths (pedagogical activities) and allow easier integration with other platforms.
Here's an example of how it looks on my Google Site (for a given course) which links to Moodle for its quizzes. The text is in French (partially), but you can understand the idea. The quiz dates (open/close) appear integrated with another Google Calendar for the course. My university provides the Google Calendar for the course (the meeting times) which I can personalize to include what we cover each week. I'm only using Moodle for the quizzes and homeworks. This calendar integration was working properly last semester, since I was only responsible for one course. This semester, I am managing several courses, and I discovered my approach won't work anymore because the URL points to a calendar that contains info for all my courses. I'm asking for a URL that points to only one course.