x's and o's

   Why does everyone in Britain sign off their texts with varying amounts of kisses. I interpret "x" to be a kiss, but maybe its just a weird signature that every British person was taught from a young age. The max I've ever gotten was three: xxx. That could also be an adult content rating, although the content of the text would indicate otherwise.
   Sometimes its combined with an emoticon, which really throws me off because I just picture someone going in for three friendly kisses with either a large grin or grimace. I do not understand the custom. Nobody wants to kiss me that much. And there are never any o's. Its never, "xoxo", only ever "x". Is a hug too intimate??? Perhaps. But then that raises all sorts of other questions.