For Newbies, its like walking into the classroom and just watching as everyone stare down at you; not the best feelings.
But yes, they are the future and we should give the same amount of respect they deserve. Not everyone is social, and I think everyone should realize that since everyone was like that at one point. However, there are ways to quickly join in and be apart of the community. One out of all ways is participating and just see where you can add your two cents. Who knows maybe your two cents will bring others and maybe yall can have a discussion? Another way to gain some friends is probably showing off some talents - users love to see what you have store and will quickly jump in to support.
Then again, older users can also help the noobs by hosting events and just helping where they can. Being friendly helps others to approach if anything, and boom a blossom of a friendship.
How I plan to greet newbies is poking them in the game or see if they want to play.