Over the past few months, it has been hard to ignore the Facebook phenomenon. An entire vocabulary of new words has emerged off the back of it, such as 'poking' and 'tagging'. The concept of 'friends' has been redefined, and if you don't have more than 100 of them, then you'd better get cracking. To some, sites such as Bebo and Facebook might seem like a pointless waste of time. After all, do we really need to know that our ex is now married and has five kids, or that our friend in Australia is contemplating eating a cheese sandwich?

But cynics daren't dismiss these sites too soon, because social networking sites can also be useful tools for business networking.

In your Facebook

Building up a network of contacts has never been so easy. Using these sites you can search for people you know, people you've lost contact with, or have only had a brief chat with in the pub. It doesn't matter how well you know them because becoming a so-called 'friend' on Facebook or Bebo is so non-committal it requires minimal user effort.

And it doesn't stop there. You can look up old friends using the 'search' tool, which allows you to search within networks of schools, establishments and workplaces. Even if you only have someone's name, you can type that in and refine your search using the filter option, specifying age, home town or relationship status.

However, as easy as it is to find someone, it's just as easy to be found. These days, anyone who is anyone has a profile page. And increasingly, employers are using the facility to research applicants, in which case you may want to re-think uploading that picture of you being sick into a bin on Saturday night, as you never know how web-savvy your future managing director may be, or how far they'll go to research you and your credentials.

Of course, sites such as Bebo and Facebook are the preferred sites of younger generations - Bebo is a fave among teenagers and Facebook among university students. Although these sites have become popular with young professionals (with 7.8 million users recorded in July 2007), they are mainly used for socialising and keeping in contact with old friends, rather than trying to drum up new business.

Richard Jordan from Ernst & Young stresses that, 'In the same way that we wouldn't cold-call new customers, we wouldn't contact strangers on Facebook to promote our business. E &Y employees tend to use the site to communicate with other people within the company. It's a great way to stay in touch with colleagues. Also, we use our sponsored graduate page to attract university graduates. They can find information on the site and ask questions.'

So, although some companies won't use these sites to approach new clients, they reap the benefits by attracting new employees and strengthening relationships between existing ones.

There are also networking sites designed specifically for business networking, such as spoke.com and plaxo.com. These types of site enable you to find people who may not be familiar with your organisation. They create opportunities to connect with them and possibly sell on a product or service. In a similar way to the famous 'six degrees of Kevin Bacon' game, social networking can hook you up with contacts you never knew you had.

For some 10 years, people have used the internet primarily as an information tool - to research anything from the population of Woking, the number of plumes on a peacock, to the British Museum's archives. Today, however, people are increasingly using it to market themselves as a brand, or to showcase a product or service.

Sites for sore eyes

Recently, social networking sites have been the subject of negative media attention. Some truly gobsmacking figures released on the amount of time employees waste on Facebook caused employers to react strongly by banning access to these sites during work hours. But these sites mark a transformation in the way we work, network and find new job opportunities. If you haven't joined up yet, it's time to get cracking. After all, critics said the same things about email and look how that panned out. Now, I must check my profile page…