Every day your social promotion strategy becomes more and more critical. Years ago it was a minor factor in search engine rankings (SEO). Now, things like the number of Facebook Likes or Google +1's are key to showing up at the top of the results.
On top of that, more and more visitors to websites are coming directly from social media sites. To keep adding new members and customers, you need to be visible on the social media platforms where they are spending their time.