Hi, I absolutely love Linked In. It has completely changed the way I network and market my services.
I use it as a referral database, so only connect with those I've met and feel I can trust (bar a few very loyal Twitterbuddies that I interact with a lot and wish I had a chance to meet) This way, when a client has a need for a service for example a new IFA, I can quickly forward a few profiles as suggestions. It's so much better than handing over a boring, corporate business card and my client can quickly see there professional experience and who recommends them.
http://uk.linkedin.com/in/tonihunterfccaThe groups are well worth spending some time on. You can't beat interacting with your potential client base and your trusted peers.
Happy Networking! :)