I do these things because I tend to follow my feelings, if I like someone I want them to know. As mentioned previously, cock is a slightly cheeky shorthand (or should that be short arm?) way of saying 'thinking of you/like you/you rock.'
I do this from an internal push to, and try to be careful of my wording with people because the written word sometimes loses important subtleties and takes on meanings you don't intend. Of course, there are times when what I want to say to people is that they enrich my life simply by their existence. If it were more socially acceptable (and in some cases, less potentially creepy/scary for the person on the receiving end) to tell people that you loved them deeply, I'd be doing that too.
It still feels weird sometimes. One of the messages I sent is to a young lady I've only spent a few hours around, but she's someone I took an instant liking to. The time I've spent with her I really enjoyed, she's one of those folks who just gives my day a huge lift whenever I think of her. She's a young Melbournite, so we're not likely to see each other again any time soon, but she's someone I could happily spend days getting to know. The message didn't go into that much detail, of course, she hardly knows me. But she's someone who deserves to know she's special.
What always surprises me is the reactions. I don't know what I'm expecting, I suppose I'm not hoping for/wanting anything except to let a person know that someone thinks they are special or important in some way. So it's been odd seeing myself mentioned on a couple of LJ's in regard to my messages.
I like, care about, and deeply love, a lot of people. It's always nice when I can let them feel that, even for a fleeting moment.
It's important to me to let people know I care, but I'm always surprised when it means something to them that I do.