Hi,
In regards to Entry #18, nice job, it's very clean and I appreciate you working with the input I provided. I didn't realize we would have so many quality entries, so ranking these is tougher than expected. I think the difference between your design and the ones ranked higher is in the degree of what I will call quick glance eye-catching ability. Those are sort of different colors, very vibrant, that pop and make people wonder what the heck that thing is. Yours is also clear, but I don't think it has the same impact. I'm not sure that helps you, but not sure how else to explain it.
I think the other entries are have some coloring issues in that the red "Ad" portion gets drowned out on the black background.
Nice job though, you're a talented designer.
Steve