There are two things to discuss - what happened in social media services and who did stuff with it. The odd bit is that the first of those was so quiet.
Yes, by all means Google launched Google+ this year but in spite of huge amounts of sign-ups - which includes a lot of people having a look around and not doing very much with it - there hasn't been a lot of noise about this service just yet. Like Google Buzz, it's failed to stand the test of time after only a few months.
The problem is that to use it you have to organise people into 'circles' - which is fine if you're starting from scratch. If you already have more than a handful of contacts this is going to mean sitting down and working up a whole load of circles in a very time consuming process.
More importantly but with a whole load less hulabaloo, Facebook Places came to the UK in January. This is the location-sensitive version, the one that lets you go to Pizza Express and claim a free meal, following in the footsteps of an American launch the year before and of course FourSquare before either of them.
If there were one new trend in 2011, predictably enough it was that social media went mobile. Apple built Twitter further into the core of iOS5 for its phones and iPads - it became taken completely as read that if you were mobile you were there for being social.
But the launch or not of particular services wasn't what made 2011 remarkable in social media. It became more of a force in its own right, for good and bad causes.
Take the spring - or more accurately take the Arab Spring. Entire Governments were brought down as people shared information the authorities were powerless to regulate. Word got outside in ways that it never would before and people held banners up proclaiming that they couldn't have achieved what they did without Twitter, Facebook. YouTube et al.
Politicians and media got it in the neck closer to home too. Flashmobs continued to be big news. The Anonymous group used social media to further their aims. It was no use trying to hide behind obfuscation if you were being questioned by a Government committee and if, say, your name was Murdoch; there would be a running commentary from the social stream and people could contact the MPs who were questioning you directly.
These could be seen as forces for good, assuming you're on my wavelength. Less positively the riots in Croydon and elsewhere were co-ordinated largely through BlackBerry Messenger. This isn't to blame the messaging service, the perpetrators would always have found something. There were calls for social media to be frozen during riot times, which would make us about the same as the dictators; when it emerged that several riots had been prevented because the police were watching the social media the coverage was a great deal quieter.
In the commercial world more companies engaged with social media than before, although figures show that not all of them respond when they are approached about something. The more sophisticated are starting to ask for precise metrics on social media - which is why companies like Adobe are starting to do well with their social media metrics product line (declaration: they had me as a speaker at the launch - it's mentioned here because it's relevant but you need to know they're a client).
We finish the year more or less where we started in terms of who's big in social media. Twitter had an investment only yesterday valuing it once again in the billions, Facebook is rumoured to be preparing for a listing and therefore huge cash influx and Google - which owns YouTube and is still therefore very much a player - still hasn't quite got it.
If we enter 2012 with anything different then it's the idea that social media genuinely can make a difference as part of an overall strategy. The Arab Spring, the British riots, confirm as much. You don't have to be on Twitter to acknowledge you can no longer dismiss it as a bunch of saddos typing on their spare rooms - although only this year BBC journalist Andrew Marr dismissed bloggers as precisely that. I wonder whether he put it on his blog.
So my summary would be that 2011 was the year in which social media started to show its potential in very real terms. I have no doubt that 2012 will continue that trend - and whatever it brings, I hope all of our readers have a happy and prosperous one as far as the economy will allow.
Guy Clapperton is the author of "This Is Social Media" and the forthcoming "This Is Social Commerce".