If you look at each letter like it was representing two people from a bird's eye view, the "O" represents the arms of those persons hugging each other while the "X" is evocative of two people kissing each other.
Xs for HUGS
Os for KISSES
Considering the fact that the Xs to me look like the way you might hug somebody. As for the Os to me they look like the way you'd purse your lips in order to kiss somebody.
2.) Xoxo is also the lazy man's also known as the shorthand way of writing hugs and kisses.
3.) Just to be short, sweet and to the point about expressing your love to someone you can always put xoxo.
Or my favourite way is
4.) The way London Tipton said it in The Suite Life of Zack and Cody "oxes to you too sweetie"
#2: A fairly expensive clothing line for young to middle aged females that mainly specializes in handbags but is not limited to just those; often found in department stores like Macy's and Foley's.
#2: " 'XOXO' has a sale where if you buy a sweater you get a purse for half off".