Facebook has over 200 million users; LinkedIn, the network for business and professionals, has over 40 million; Twitter is all the rage; and don’t forget blogs.

Although these services are hugely popular, it’s safe to say that amongst lawyers use is still largely confined to so-called early adopters. Should you be using these (public) social networks? If so, which? for what?

Too often answers to the question “Why should I use social networks?” focus on particular features each service offers and for what tasks they can be used. But it is worth first understanding how they work, their similarities and, more importantly, their differences. Then consider the numbers and the demographics and the benefits of making balanced use of some or all of these services – according to taste – should be clear.

Who you know

Facebook is a free-access, privately-owned social networking web service. It acts as a super-charged social address book – a destination where you can connect and interact with “friends”, see how they are interacting with their friends and also connect to others with whom you have a looser social connection (all those in your workplace, college or region).

Post your profile, add some friends (subject to their confirmation) and you’re away. Say what’s on your mind, see what’s on theirs, add more friends along the way, set up social events and much more via built-in Facebook features or one of the countless third party applications.

Founded initially for use by college students, Facebook is now open to anyone over 13, with the UK proportionately the most enthusiastic adopters.

Although it can be used for professional purposes, it is primarily used for social interaction and its largest constituency remains the 18-25. Indeed, it is so dominant amongst UK students that not to be on Facebook is to be all but invisible to your peers.

Who they know

LinkedIn is again a privately-owned social networking service designed for professional and business networking. It is free to use but with certain extended features available to paying subscribers.

Your profile on LinkedIn acts as your online CV, describing your experience and expertise and enabling others on the network easily to find you and connect with you. All LinkedIn public profiles are also indexed by Google, so your profile becomes another valuable property in your online portfolio. LinkedIn is fast becoming the online directory of business and professional people.

You can invite anyone (whether a LinkedIn user or not) to become a connection or can request to connect with another user via a pre-existing relationship or the intervention of an existing contact. This “gated access” approach is intended to build trust among users.

An important feature of LinkedIn is its emphasis on “degrees of connection”. Your direct connections are your 1st degree connections; their connections are your 2nd degree connections; their connections are your 3rd degree connections. On every screen you are reminded of these degrees of connection and invited explicitly or implicitly to extend your network by connecting directly to current 2nd or 3rd degree connections.

LinkedIn emphasises degrees of connection because, in business, it is often not just who you know that counts; it is who they know.

What you know

Blogging is not a service owned by anyone: your blog is yours and the Net is the network. Unlike Facebook and LinkedIn, the emphasis is not on who you know, but on what you know. With blogging you demonstrate your knowledge, expertise and personality through your writing. You connect with other people not explicitly, but by linking to and commenting on their blogs. Likewise, if you have something useful or interesting to say, others will link to and comment on your blog. Blogging is thus a mutually reinforcing ecosystem of authors and commenters of like or overlapping interests.

Blog search and analysis services such as Technorati and Google blog search work by highlighting the connections between blogs and enable you to readily search across them and extend your blog network.

Whatever

And so to Twitter, usually referred to as a social networking and micro-blogging service. It shares some characteristics of both social networking and blogging, but it is the differences that are most revealing.

Twitter is deceptively simple in functionality, yet its essence is fiendishly difficult to explain. Indeed, the most common early tweet by new users is something along the lines of “I don’t get it.” Even those who have become avid users admit that it took some time before it clicked.

All you can do on Twitter is post short messages of 140 characters or less and read those posted by others. You follow those whose messages interest you and these are displayed in a “stream” on your Twitter home page. (Users can protect their updates, requiring their permission for you to follow them, but few do.) Likewise you are followed by those to whom your messages are of interest and your tweets show on their home page.

Unlike Facebook and LinkedIn connections which are reciprocal, Twitter connections are asymmetric: you choose whom to follow; others choose you.

As with blogging, Twitter connections are also made indirectly by linking to others – responding to or “retweeting” their tweets or referencing them in your messages.

Twitter’s prompt “What are you doing?” is somewhat misleading for new users, suggesting that its main purpose is to post status updates. But what you use it for is entirely up to you. The 140-character constraint forces brevity: pithy comment, banter, breaking news headlines, link sharing; these are all meat and drink to Twitter users.

Twitter is very much flavour of the year, but don’t be impressed by headlines that proclaim 20 million Twitter users and growing at 1,382 per cent per annum. Recent research reveals that 60 per cent don’t contribute after a month, so we have 8 million active Twitter users. That’s a sizeable number, but it does not make Twitter mainstream. And 90 per cent of all Twitter activity is by 10 per cent of users, giving us only 2 million users worldwide who fully embrace it. That’s not going to change the world, much as that minority would like it to.

Conclusion

When it comes to socialising, Facebook certainly looks likely to be the winner who will take all (see bit.ly/1A2z5k), but I’ve yet to be convinced that it’s a must have or even a nice to have for business.

For doing business we must look to the more focussed service that delivers business benefits. LinkedIn has always sold itself as the network for business and professionals and it is so. Despite its continuing rapid growth – with over 43 million members in over 200 countries – it has not grabbed the headlines, being too worthy and boring for lazy hacks to comprehend. Because it has focus, the increase in usage has not produced a lot of noise. Though Stephen Fry has heard of it, thankfully he has not yet found a use for it and he lurks in the shadows.

Blogging is good for business. But it takes effort and commitment.

As to Twitter – give it a go. If you make an effort, you never know what might happen.

Nick Holmes is joint editor of this Newsletter.

Email nickholmes@infolaw.co.uk.