While there are many opportunities to connect and showcase yourself online, there is no way around the fact that you simply must be using LinkedIn. If you aren't using its features to their fullest, you may likely be missing out on opportunities to connect and impress.
Show Me, Don't Tell Me (Reputation and Credibility)
Research (Overt and Covert)
LinkedIn as a Sales Channel (How to do it well or totally blow it)
Joining Groups (The Good, The Bad and The Ugly)
Crowdsource Knowledge and Expertise