This is just another way of saying race is irrelevent to the person. WWF seeks soulmate. Not everyone uses these abbreviations, but a lot of people do, because they make it easy for people to spot you and know if you're at least in the ballpark of what they're looking for. You may see variations on these abbreviations that you don't recognize, but usually you can figure it out from context once you get the trick of it. Ah, there's a whole lot to be said here, and the advice can vary a lot.
Some people are big fans of cute and creative subject line.
Now this is pretty funny, and pretty clever. By making sure your subject line contains your basic information, you will not only be doing everyone who would NOT be interested in you a favor, but you will increase the likelihood of someone who DOES want to meet you of actually spotting your ad. All right, you've given a nice, concise, descriptive title to your message. Now you need to put some thought into the ad itself. You have plenty of time to write this.