I know that shorter messages are better in terms of reply rate. The optimal length is something like 50 characters. Characters, not words.
Christian RudderDudes have been making up stuff about themselves probably since there have been dudes.
Christian RudderA great piece of advice for online dating is to stand out from the crowd. So greetings like "hello" and "hi" are very common. They do less well than things that are a little bit quirky or a little bit weird, like "howdy" or "holla." The rarer your salutation, the better it does, in general.
Christian RudderWomen are much more discriminating. I think both types of people are equally interested in having an attractive partner. But women essentially give the thumbs up to only half as many guys as guys giving the thumbs up to women.
Christian Rudder