Servicemen are required to have uniforms, uniform haircuts, restrictions on jewelry or tattoos and behavior.
If they stay on post, the periodic inspections of post housing for health and welfare will force even one's home to be uniform and generic.
This becomes even more pronounced when deployed.
There is little which can be done other than military activities or activities which are approved, and youngsters tend to want to have more of a chance to let their hair down so to speak.
Without the opportunity to bring more than tiny amenities, there is little chance to make a hooch into a home.
Even if some posters or such are available to allow some customization of living space, it is likely that the sorts of things which soldiers would want to put on the walls would be forbidden and removed when found.
Social networking sites allow people to connect by searching for common interests.
These can be music groups, movies, poetry, and politics or just about anything else.
While service members have more restrictions on their civil rights than other citizens, there is a certain amount of leeway granted when outside of the strict military situations.
One real advantage to these sites is that even when overseas and subject to General Order #1, with nothing but military gear and uniforms available, the website can be personalized as desired.
Some sites allow the user to imbed music or multimedia into the page.
Some sites allow extensive use of pictures.
Some allow extensive commentary by other users on a page.
All of these create a sense of individuality.
The degree of anonymity which the internet can provide can be liberating.
Especially for those who have to keep everything tightly wound and controlled, being able to let your inner geek out over whatever topic excites you can provide the outlet needed to get through the next tribulation.
It is even possible to discover that people you already know have interests you'd never suspected from what they place on their web sites.
From a tough soldier who knits in his spare time to keep his hands busy while he watches television to fans of sports which simply aren't popular in the US, and who thus have no reason to talk about their secret obsession.
You might also find connections through friends of friends, and develop direct relationships with those people over mutual interests of some sort.
With the mobility of the service, it is likely that at some point you will be around these people, and knowing something you both agree on is certainly a good first step.
Finally, your social networking site remains a place you can carry with you anywhere you go, provided it has internet access, can decorate as you desire, provided you don't violate terms of service, and which can show the world those things that you believe make you special, no matter what they might be.