It has now been 51 weeks, more or less, since Google introduced Google Plus.
Google+ was the third attempt by Google to introduce a social networking site, the first being 2004's Orkut, released shortly after Friendster first became popular (and which for some reason, obtained a largely Brazillian userbase, and which is still popular in that country). The second, Google Buzz, was launched in 2010 and lasted for a year. Neither Orkut nor Google Buzz seemed to find a market niche, and they barely made a dent in the series of social networking sites that did dominate the internet. Friendster, Myspace and Facebook all had much less impressive technical pedigrees than any of Google's social networking sites, and yet they all managed to dominate the market.
After a year in use, Google Plus is neither an abject failure nor a roaring success. It built up an early impressive user base, based on people who already had google accounts (and in many cases, who were google employees), and has seemed to coast for the past year, despite being opened to the public. I have a Google Plus account, and while it has its fair share of interest, it has not managed to expand or differentiate itself from Facebook, the current standard of social networking.
The Google Plus experience, and appearance, is modelled on Facebook, with only slightly different bells and whistles. You have friends, who can be divided into circles (a functionality also present in Facebook, but not as obviously available). They post and you comment. You "+1" something instead of "liking" it. You can post photos in albums.
One of the original selling points of Google Plus for some was that it would not be as widely populated as Facebook. An xkcd comic makes this point: that your parents won't be using it. With only the internet cognoscenti using it, Google Plus would have more geeky discussion, and less forwards, game spam, and pointless discussion. Which is somewhat true, but not to a meaningful extent. Google Plus, a year after its founding, is a slower version of Facebook with a different user base.
Why Google, the company that became synonymous with "search engine", and has also dominated internet mapping and webmail through innovation and quality, is unable to find as much success in the field of social networking, is an interesting question. Many other internet powerhouses of yesteryear, such as Microsoft, AOL, Yahoo and MySpace, have been unable to understand what the market wants and how to adjust to changing user demands. Whether Google's mediocre showing in social networking is a sign of a larger weakening of the company's understanding of its market, or rather is just a situational weakness in the social networking field remains to be seen.