Create a Facebook group to engage in back-and-forth communication with your clients. Use it to gain feedback about your product/service. Put Facebook 'Like' buttons on your website like we have here, and each time someone 'Likes' it, they tell their friends about it on their wall, and so word of mouth about your business spreads.
Twitter is one of the best way to increase traffic of the website.Increase your network by following friends and post regularly on your profile about your websites features,updates,blogs etc..Get some suggestions from them about your site.
I read some reliable source regarding Facebook that each post "like" from a viewer will not surely turn into a good viral activity. But then when you create a high quality, organized, and efficient content, viewers will shared it surely. For social media marketing, fan page in Facebook will also help you. Just ensure remarkable and efficient page such as inserting logo, posting regular updates, and building good social relationship among the viewers.
if we talk about twitter as compared to facebook and other social media sites then working on twitter is a bit difficult because if we want to get desired results then we have to spend too much time on it to tweet and get feedback from your followers...
Not just twitter or facebook but all social sites are good for business but the need is to provide best and unique information every time to our visitors so that they want to get more and contact us for that.
In Twitter, you can gain good numbers of followers wherein somehow can turn to audience and later customers. But then, you have to ensure the reliability of each information you are posting or sharing because that is one way to get more people for your business.
As everyone mentioned, social media is great to bring traffic to your website. You had a great question, if your friends/fans don't want to share the post, is there still benefit?
By posting regularly you are increasing your brand awareness. Your fans may not be ready to share the post with their walls, but they did "like" you for a reason and I would suggest to continue to provide relevant information to them. By your communication you will hopefully make it to an "unaided recall" type of relationship with them. Also, just because they aren't sharing it with their friends on Facebook, doesn't mean they aren't talking about the posts in face to face conversations.
Social media is about building relationships in an effort to increase your sales. You might not see a difference right away, but people don't go on Facebook to go shopping - they go to interact with their friends and favorite pages (companies, celebrities, causes, etc.). Develop a relationship so when they have a need for your product/service they think of you. Once you exceed their expectations they'll be more likely to share with their friends!