I usually don't because it's just not my style. I think it gives the girl the upperhand because afterall you are finding her on the internet... If things DO work out, she'll eventually get curious and want to know how you found her in the first place. I stick with opening in person... then using text game. I NEVER add a girl on facebook as a friend, if she's interested in me after I meet her then she'll add me as a friend.
But, others have had success with online sarging...
online-sarging-vf50.html