Below is an overview of resources, tools, services which can help you in taking your first steps into "social media world". 

Resources I use during training:

RSS Mixers:

Feed Rinse:

Feed Rinse is an easy to use tool that lets you automatically filter out syndicated content that you aren't interested in. It's like a spam filter for your RSS subscriptions.

Yahoo Pipes:

Pipes is a powerful composition tool to aggregate, manipulate, and mashup content from around the web.

Dashboard:

KlipFolio:

Track personalized RSS, weather, news, blogs, and more with the world's smallest personal dashboard.

Social Networking:

Linkedin:

LinkedIn is an online network of more than 25 million experienced professionals from around the world, representing 150 industries.

Facebook:

Facebook is a social utility that connects people with friends and others who work, study and live around them. People use Facebook to keep up with friends, upload an unlimited number of photos, share links and videos, and learn more about the people they meet.

Micro-blogging:

Twitter:

Twitter is a service for friends, family, and co–workers to communicate and stay connected through the exchange of quick, frequent answers to one simple question: What are you doing?

Jaiku:

Jaiku's main goal is to bring people closer together by enabling them to share their activity streams. An activity stream is a log of everyday things as they happen: your status messages, recommendations, events you're attending, photos you've taken - anything you post directly to Jaiku or add using Web feeds.

Tumblr:

Tumblr: To make a simple analogy: If blogs are journals, tumblelogs are scrapbooks.You can also look at tumblelogs as slightly more structured blogs that make it easier, faster, and more fun to post and share stuff you find or create.

Wikis:

WikiMatrix is a "search and find" / comparison website which allows you to find the right fit for your use of a wiki platform.