My personal experience is that in my company there are more than 100 employees, I may not be interacting with all of them but if i have a connection on social media site if I feel connected with them. Henceforth Creating company group where employees can interact or communicate is one of the best activity to make them as a team.
3 Social Media Sites which can help in connecting employees:
That was for sure since it is the second ranking website (result may vary) but yes you can create a company fan page or a group where you can interact with your employees on new issues, news or simply their recommendations I have seen many companies use Motivational quotes on their facebook group page which is another good activity you can carry.
LinkedIn is considered as one of the best social website to connect professionals. On LinkedIn you can create a company page and cultivate different activities. Another advantage of having LinkedIn is that you can even connect with your clients which will increase the brand loyalty.
Another way of getting connected with your employees is using google hangouts specifically for those who are working onsite or travelling.
Other ways where you can get connected with employees via social media
Twitter - Employees can follow company twitter account and can retweet tweets to create greater effects.
Pinterest - On Pinterest you can create a board for employees which engage everyone for decision making
What other social media you feel would be better interacting with employees - Comment