A relatively large number of publishers, particularly those running ‘blogs‘, rely on third-party services to power the comments on their websites.

From Facebook Comments to Disqus, there is no shortage of options that enable publishers to offer commenting functionality without having to implement it themselves.

While not the most technically complex functionality to implement, there are a number of reasons publishers might choose to outsource comments, ranging from spam control to identity management.

Up until now, however, Google hasn’t always indexed all of the comments left by users, as solutions like Facebook Comments, Disqus and Intense Debate rely on JavaScript to function.

That is apparently changing according to Amit Agarwal of Digital Inspiration. He writes:

Googlebots, or the spiders that crawl web pages,  are now reading Facebook comments on websites just like any other text content and the more interesting part is that you can also search the text of these comments using regular Google search.

Observers will be quick to discuss the potential SEO implications here, and there may indeed be some for certain publishers, but in reality, the biggest implications may be for individual users, particularly those who comment using Facebook Comments.

After all, Google’s access to Facebook member information is limited when users apply the appropriate privacy settings to their Facebook Profiles. But comments left via Facebook Comments give Google a back-door opportunity to tear down Facebook’s wall.

As launch.is demonstrates, a person’s name and their university can be used to surface comments that he or she has left across the web, and in some instances, those comments may appear on the first page of results for that individual.

Obviously, one would expect that users posting comments through their Facebook profiles would understand that those comments could be visible to search engines, but now that Google is actually indexing them, you can be sure more than a few users may be surprised to learn that their online commenting activities are now a part of their Google track record.

How many of them are upset by this only time will tell, but Google’s move does serve as a reminder that as Facebook seeks to play a larger role on the web outside of its walled garden, its users will increasingly find that maintaining their privacy requires greater and greater effort.