Exchange agencies usually recommend as little contact with people in your home country as possible. From what I have experienced, I think this "need" is individual. If skyping your family every day, week or month prevent homesickness, do it. If it has the opposite affect, try to moderate the amount of contact. There are several reasons why organizations tell you not to spend too much time on your computer, chatting with family and friends. As you arrive your host country, you are expected to "quickly" integrate with your new family and community. This process might go slower if you're preoccupied with what's happening in your home country. I must admit that I found it very challenging to live with one foot in each country. It's almost impossible to live two seperate lives. Finding a good balance is also hard. My advice to you is to have your main focus on what's right in front of you. Don't shut the people in your host country out, but make sure to give enough room for your new life.
Remember; Yes, It's a life in a year. Yet, it's just one year of your life.