It's not a big deal
The most important evaluation that has to be made about a kiss is if it's a "big deal". If it's not, then why does it matter? This conversation is a waste of time. However, I would say most people wouldn't walk up to a stranger and kiss them. It is somewhat a big deal, and takes a certain degree of intimacy before people take that step. But how big of a deal is it?
Let's look at a married couple. Is it a big deal if they kiss someone else? Yes. And the fact of the matter is that some day most people will marry. So, as you are kissing someone, you are kissing someone who one day will be a husband (or wife) to someone.
Well then, when?
However, I also believe that intimacy is an important part of any relationship. I don't think it's good to have a set-in-stone rule that it's a sin to kiss until you are married. However, it takes commitment. I believe that kissing someone who isn't, at least one day, your spouse, is nearing the line of cheating on them. Therefore, the way to avoid this is wait until you know they will be your spouse- engagement. Though it's not a marital covenant, engagement is a commitment and promise, and therefore should only be broken in "extreme situations."
Emil Ludwig (1881-1948) said, "The decision to kiss for the first time is the most crucial in any love story. It changes the relationship of two people much more strongly than even the final surrender; because the kiss already has within it that surrender." I would add that surrender, done without commitment, is a dangerous emotion that frequently ends in people getting hurt and having regrets.
There are alternatives
As I stated before, intimacy is important in a relationship. Some people argue that kissing is a way to show affection, and I would agree. However, there are alternatives. A sweet note telling them how you feel shows affection. So does holding hands. The danger with kissing too early is kissing leads to other things. My roommate puts it comically (completely joking): "Kissing leads to stuff, and stuff makes you explode." She does have a point though: kissing is designed to lead to other stuff. A Chinese proverb says that, "Kissing is like drinking salt water: you drink and your thirst increases." Basically, I believe that it's important to keep things simple and uncommitted until there is a commitment.
Again, I understand that there are several different opinions on this, but I wanted to share where I am coming from. I would love to hear your comments, annonymous or named and welcome any discussion-sparking questions. I will withhold publishing if you'd like by mentioning that within the note.
Another good perspective here.
Picture by julpi http://www.flickr.com/photos/julpi/487152184/. Creative Commons liscence: Non-profit and non-derivative.