The social media conversation always, albeit implicitly, pits Facebook against Twitter. It sounds reasonable on the surface, given that they're the two biggest brands in the space. It's also a very ignorant comparison because Facebook and Twitter are fundamentally different products. Google Plus, however, is much more like Facebook, even more-so with its latest redesign.

Google Plus' circles is a mimick of Facebook's groups. Both let you filter your news feed, and both let you restrict your posts to an approved set of people. The new profile page design on Google Plus has even shamelessly copied the cover photo from Facebook's Timeline profiles.

Google Plus has been set up to present photo albums in a stylish way that is said to have attracted many photographers. Meanwhile, Facebook is the biggest photo repository on the web, and has recently updated its photo presentation to match Google Plus' design.

Of course, one of the most fundamental moves that Facebook made to retain its users was to implement an application platform. Thanks to partnership with games company Zynga, Facebook attracted, retained, and made money from its users. Google Plus has tried to follow suit with releasing a games platform.

Given Google's wealth and popularity, especially with Android, why hasn't it had better success with Google Plus?

There are three answers to that question, and the answers are surprisingly unlike Google.

Firstly, Google Plus lacks an Application Programming Interface (API). Facebook has an API which is what allows you to use third party apps and services to post content to your account. Whenever you grant something permission to post on your wall, you're going through the Facebook API. Google have still not done this. So it's relatively inconvenient to use because there's no way to post content without using the website or Android app, and Google have not provided an app for other mobile platforms – which brings us to …

Secondly, Google is pushing its social network via its mobile platform, Android. All other mobile platforms have so far been ignored, apart from having a mobile version of the website. Google's attitude has always been that as long as people are using its services, then it benefits. Now, it has chosen to act in a far more closed way than it has ever done before.

Thirdly, as a consequence of the above two points, Google Plus runs the risk of engendering apathy and hostility; Apathy because Google has not made it easy enough to use Google Plus (e.g. there can be no TweetDeck integration without an API); Hostility because the public could well be turned off by the relatively closed and forced environment.

Google Plus' popularity grew very quickly compared to Facebook and Twitter. However, it's probable that its growth has slowed significantly – especially if the quantity of new posts is anything to go by. I know that most of my Google Plus 'followers' are new users who rarely post anything, which looks suspicious – possible spammers in the making?

Hopefully, this year's Google IO developer conference will bring a Google Plus API – if it doesn't it runs the risk of letting its social network slip into irrelevancy.