In my case it wasn't a problem of checking the social networks often but being in a constant need of checking the news: International, national, local, technology blogs, etc. So I noticed that was stressed and over-saturated of information.
To be honest when I was working in a website I was often tempted to check my facebook and twitter account too, and although it didn't take too much time it made me lose my focus.
I decided to put a solution to this and became disciplined enough to check my social media and news only once a day. I look at it in the evenings, after dinner, when I am out of my workplace.
Regarding the "news feed" I have decided to listen to my favorite radio station instead.

With easier access to the internet in the work place no matter you work in an office or from home, its very easy to lose focus. If you have a smart phone, social networking sites like Facebook, Twitter, Linkedin can easily tempt you to log in to check what your friends are doing or whats happening out there. It becomes my habbit that in the morning, the first thing I do is check my facebook and then twitter account.

Therefore, its a good idea to allocate certain time to check the updates. For example, spend 10 mins in the morning, 10 mins in the lunch time and 10 mins in the evening to do all the social networking that you want. And then during the work time, just turn your phone off.

It also helps to make a target for yourself everyday, and reward yourself when you finish it.