The existing people you have in your address book are all the contacts you need to begin building your social network from the ground up.
Information you have already collected whether through your cell phone, Microsoft Outlook or Mac Address Book and online services like Gmail can help you connect quickly to friends through networks like Facebook, Twitter and LinkedIn.
You can create a profile on Facebook in a matter of minutes and begin searching for friends by email address or name.
Once you find a friend and confirm that the picture actually does look like Jen from high school you can click the add as friend request and wait for the email confirmation that Jen does indeed want to be your friend in this decade.
Having up to date email addresses can help you find your friends faster as new people are joining Facebook all the time.
This popular social network has more than 500 million active users with 50% of those users logging in regularly.
The average user has 130 friends so it won't take long to build up your network if you are new to the website.
If you already have an account, check to see who has newly joined as you may find that friends or contacts you haven't seen in ages are now expanding their social networks too.
Other social networking sites like Twitter are also easy to join.
Invent a really cool user name, set your password, click the "create my account" button and you are set.
After confirming your account, you are able to search for people by name or even invite friends to follow you by sending a form request via email.
Twitter makes it easy to find friends by searching through your email clients like Yahoo, Gmail, AOL and LinkedIn.
It will identify contacts and let you know if they have an account.
You can easily start following your friends tweet's and ask them to follow you as well.
LinkedIn helps you connect with past and present colleagues as well as old classmates.
It can help power your career when you are looking to make connections in your field by giving you access to other professionals.
Like Twitter, LinkedIn searches your email contacts to make it easy for you to find people that you already know who are using the site.
By using your existing contacts, you will find it very easy to build your social networking skills and have access to friends and colleagues from all over the world.