People go to social sites for socialization.
For example someone try to find out some of his old school friend.
A son may be in overseas. Mother is in the country home. The son uploads his recent photographs so that mother can see them. These are socialization.
But unfortunately we see that all are trying to sell there as like as it is not a social site rather sale sites.
The attempt they are taking making the user angry and block their account.
So if you want to sell first socialize. Once you have friends then they will automatically know what you sell. Due to the friendship they will be obliged to buy your products.
The best thing for socialization is try to help people for their need. If someone ask any information in your blog comment you should give it. Once he takes you as a friend and depend on you he will take your advice to buy products from online.
Socialize should start from helping each other with the right information and assistance to gain confidence that will lead to sell.