MySpace is a distant memory, LinkedIn is used just for resumes and services like FourSquare, Plurk, Ning and others are not well-known.
Also not that well known is Google Plus, and perhaps rightly so - it is very new and still quite small in social media terms, only around 62 million users, although it is predicted to grow to over 293 million by the end of 2012, or so Google believes.
However with the recent integration of Google Plus into Google search, it may be time for governments to consider establishing Google Plus channels alongside Facebook and Twitter, due to the impact on search results.
With Google's search tool holding close to 90% of Australia's search market, it is a more dominant 'publisher' than News Limited - and remains the number one website in Australia. Search engines are also the primary source of traffic for Australian government websites, with an average of over 40% of visitors reaching government sites from a search engine (according to Hitwise) - and therefore around 36% coming direct from Google.
So what has Google done? According to Gizmodo, they've integrated Google Plus into their search product in three ways,
First, it now provides "Personal Results" which include media—photos, blog posts, etc—that have been privately shared with you as well as your own stuff. Any images you've set to share using Picasa will also be displayed. Second, Google Search will now auto-complete queries to people in your circles and will display people who might also be interested in what you're searching for in the search results. Finally, it simplifies the process of finding other Google+ profiles for people or specific interest groups based on your query. So if you search for, say, NASA, it will display Google+ profile pages for NASA and space-related Google+ interest groups in addition to the normal results.Whether you believe this is a good move, a legal move, or not, it does provide opportunities for organisations to leverage Google Plus to improve their overall presence in Google search by operating a Google Plus account.
It's certainly something to keep an eye on, if not actively consider.