As the old saying goes, it's not what you know but who you know, and nowhere is that truer than on LinkedIn. Launched seven years ago with the ethos that effective networking breeds success in the workplace, the social network for professionals now has more than 75 million users and numbers are rising as job insecurity grows. So how can you make the most of it? We trawled the CIO archive for our five top tips:

1. See yourself as others see you:
It goes without saying that to market yourself effectively you will need to present yourself in your best light. A concise and engaging summary, comprehensive work history accentuating your strengths and highlights, and a professional – and current – photograph are the essential building blocks of a strong profile. That does not mean embellishing your achievements: given that your bosses, colleagues and customers can all see your profile, there's not much point being dishonest. Ensure that your profile is public so that people can search for you and include keywords that people looking for somebody in your field might search for.

2. Be generous with your contacts:
It's up to you whether you accept LinkedIn's guidelines and only make connections with people you know personally or copy the approach of the so-called LinkedIn Open Networkers, or LIONs, and add people whether you know them or not in the hope that you will benefit from this approach. Either way, once you've made connections, don't be shy about recommending others. The recommendations feature is a powerful way to show your value and if you write a good recommendation for a colleague, the likelihood is that somebody will do the same for you. Finally, make your connections list public. This allows your contacts to make connections with each other.

3. Make use of alerts:
LinkedIn allows you to save up to three searches and will then alert you if anything new happens to do with those subjects. If you are looking for a new job, for example, and have defined the prospective role, geographical area and sector and saved the search, LinkedIn will alert you when a new person signs up who matches your criteria.

4. Join groups within LinkedIn:
Groups can raise your visibility by putting you in touch with a wider network of people in your sector. They also allow you to get in touch easily with people who aren't in your connections list since you can send direct messages to anyone in the same group. CIO UK's LinkedIn Group, for example, allows CIOs to network and join a range of topical debates.

5. Use your connections to bring in business:
In these harsh economic times, every CIO is looking for ways to bring in new business in order to justify their budgets and improve their professional reputation. One way to do this is to use sites such as LinkedIn to discover new sales leads. What better way to get a foot in the door with a new company than through a contact of one of your colleagues?

Do you already use social networks to network, recruit or find jobs? Post a comment below.

Pic: nan palmero cc2.0