People are asking me to add them as a friend in social bookmarking sites. I can see that some people have lots of "friends". What are these friends for? Does it help with something to have lots of "friends" at these sites? Or is it just for teenagers who want to chat?
They build friends to know about their site to each one,to get traffic and to improve its page rank,they exchange link buildings etc..Social bookmarking is a good place to get traffic.
The more friends you have, your profile will be visible on more pages of that social bookmark site, and so, there will be an increased chance of people visiting your page by browsing through other pages. When they visit your profile page, they will be likely to visit your site too, if they find it interesting. Also, some social bookmark sites can also pass PR to you, if you have a popular profile page which has gained PR over time.
Many of them submit their blog in social bookmarking sites to get tons of traffic daily and to increase their page rank.U can digg the sites, you like in social bookmarking and by this way,u get traffic too.