Stop being "desperate" and you might get more responses.
One thing a lot of people don't realize, probably especially male subs (and I had to learn too, so I'm not immune to this comment) is that desperation tends at the other end to breed repulsion, or at the very least, severe caution. Most Doms and Dommes are not looking for a random person to dominate. Most of them are looking for people with some degree of personality and potential long term relationship, not necessarily a sexual relationship, not necessarily a relationship with the sole focus of BDSM. A person committed only to a one time fling or expressing interest in only a BDSM focussed relationship may not be very appealing to many. I'm sure there are some Doms and Dommes out there who are different, but what I am relaying is basically what I have been told by a number of respected people in some of the different communities I have hung out in online.
Yes, I know that online is different from real life, but I do believe that one can learn a lot about a person by observing how they interact with others online over a period of time. Eventually, it is not difficult to determine the fakers from those with a genuine interest. Also, it can be a good learning tool to determine for yourself what type of personality you seem to jibe well with online, because chances are the same type of personality will jibe well with you in person, assuming of course that both you and the other person bring nothing short of sincere and total honesty to the equation.
Keep in mind also that as a male sub looking for a female Domme, you have a tremendous amount of competition with other male subs, and consequently female Dommes have lots of potential pickings from which to choose, so if you really want to get the attention of a Domme, you must make yourself pretty special in some way to draw their interest to you. Like the old expression goes, "beggars can't be choosers." Show some personality, either on the forums, in a chat room, or on a blog. Stop asking incessantly if somebody will dom you. Stop pretending that dominants are a dime a dozen (because dominants really hate being thought of that way). Instead, let the Doms or Dommes know as much about you as you feel comfortable sharing, and the more you feel comfortable sharing, the more honest you appear, the more likely you will attract the attention of that somebody by your actions rather than your words.
This can take a long time, but I am proof that it can be done. I still haven't met my Domme in person yet, but I am confident that when I do, it will be a very positive and memorable experience for me.
Good luck on your continued journey.