The new and growing requirement to reference a website within social networks and generate "Buzz".

As Google itself advises, "get involved with the community around your topic".  This is not only a question of participating in Social media like facebook, but also participating in, and contributing to, forums.

"Connections" are the power-core of Social Network optimisation.  Do the right things, (as suggested in these pages), sure, but obtaining the connections - is up to you! (Which, by the way, is also why Search engines are increasingly looking to Social Media to assess a site's popularity.)  Doug Firebaugh, Social Media Strategist says the 5 step approach to turning social media into a customer avalanche is:

1) Connect -->  2) Conversation -->  3) Value -->   4) Doorway -->   5) Customer
 

To "Connect" you have to be visible on the media and then connect with the people that are searching for you.

Pay attention to people who follow you and feed them regularly with quality food!

Give people more value than the next person to keep them "sticky"

The "doorway" activity (where a follower turns into a customer) is where you give people an offer that they find hard to turn away from.

And when someone becomes a customer, do not leave things there.  Follow-up with other offers and even free gifts when people are not expecting it.