The subject of Facebook has cropped up quite a lot recently in enquiries I’ve had from law firms.

I don’t know why, Facebook has been running for many years so it’s hardly new. Maybe Spring is in the air and firms feel they need to do more on their marketing, especially on the social media side.

The question is: should Facebook be part of their marketing mix and how do they go about it? This is an awkward question for me because my instinctive response is to say, unless you’re really committed, don’t bother. Facebook isn’t like Twitter, or LinkedIn... or even Pinterest.

For marketing purposes, Facebook is difficult... it’s time-consuming, involves lots of work yet the rewards are very uncertain. To make matters worse, you can’t be sure that Facebook won’t cut the ground from under you just as you’re on the verge of success.

I should point out that I’m not talking about Facebook advertising... the stuff you pay for. I have my doubts about that but that isn’t the subject of this article. I’m talking about the organic social interaction side of Facebook; the kind of marketing that’s free in theory but which in practice may turn out to be very expensive.

Let me explain. The basic premise of Facebook is that you set up a page and put interesting posts about your firm and its services, legal developments, news stories... anything that will catch the attention of the public so you can build up an army of followers.

So far, so good... but there are problems.

Facebook is far from straightforward. Its system is set up so that your posts are only seen by a small proportion of your followers, currently about 10%. This means that if you have 1,000 followers, only about 100 will see any particular post.

You then hope that some of those 100 will find your post interesting enough to share with their friends or followers. This way you will reach a bigger audience. If one post goes down very well and gets lots of shares, Facebook may slightly increase the number of people who see your next post. If that gets lots of shares, you may get a virtuous circle going.

However, it can go the other way as well. If your post doesn’t create much interest you’ll be back where you started.

This means that how many people you reach on Facebook is determined by how popular your posts are and how many people share them. It’s not enough to have large numbers of followers; you also need to produce lots of interesting posts.

This presents difficulties for law firms. The law is a serious matter yet Facebook is a medium designed to allow friends to interact socially in a light-hearted way. As people put up pictures of their boozy Friday night out, how many of them are going to share your law posts?

The question of what material works best on Facebook is another concern. The most popular posts involve pictures, jokes, amusing or inspirational quotes... none of these are all that high on the law agenda.

The other problem with Facebook involves something we can’t predict: what will Facebook do next?

Its practices aren’t set in stone. For example, until early last year, Facebook used to automatically show your posts to somewhere between 20% and 30% of your followers. Then its share price fell, so it cut the figure down to something like 10% - presumably to persuade firms to pay for advertising instead of trying to reach people organically.

Who’s to say Facebook won’t reduce the percentage even further? It raises the question: who wants to put a lot of time and effort into a marketing platform they don’t control and which may change for the worse at any moment?

So, should your firm get involved in Facebook? Well, maybe... but only if you’ve already got more certain and reliable marketing strategies in place. Facebook should be one of your last marketing platforms, not one of your first. And if you are going to do it, you need to go into it wholeheartedly with a lot of resources behind you.

As we’ve seen, it’s full of challenges and is not for the faint-hearted.

As for that social media platform Twitter, well now that’s a different matter altogether. I’m much more positive about Twitter... but more about that in another post.

Nick Kehoe is a former television and newspaper journalist. He is now managing director at law marketing firm Media Coverage