The kids are still there. They continue the friendships that they had before. My daughter's last year in school was the 2nd grade. She has continued her friendships even though all of them are now in different schools. If you are reading this, then obviously you have computer access and an online service.
Kids can talk to each other using the computer and chat lines.
Both lists have names for both parents and students. Children can also participate in sports, 4H clubs, other social groups and they can join church activities. The social opportunities are out there. In the early years, I think homeschooling is best because the child focuses on the education and not just on playing. The child then gets his basic academics down and can succeed in any classroom setting.