After going through years of having to periodically change networking sites, or have multiple accounts I had to check, I am completely happy with facebook- because its a STANDARD. Practically everyone I know has a facebook account and I know I can get into contact, set up plans, share photos, etc. in ONE place.
Any "alternative" to facebook is going to be limited in scope and membership. You would also have to make all the people you want to communicate with have to set up accounts,
then you are back to keeping passwords and site addresses so you can talk to these family members, then another set to talk to those people, and another site to talk to them guys or gals, then, before you know it, you have a big mess and don't remember which people are on which networking site, you forget to check one for a month or two,etc.etc. etc.
Facebook does the job it is intended to do- basically serve as a directory and connection point to practically anyone, it is the
de facto standard for the world
The whole point is social networking, and thats what facebook does very well.