The total amount of male members would amount to 300 to 400 thousand but about active rate I have no idea. This result come from our search engine. As we select men to send admiration letters to, we search for proper ones according to the standard ladies set (sometimes you can see their standard in profiles). I have once set the time of regisration from foundation of chnlove till the time I made the search and age from 18 to 99, and got that result. It varied slightly every time. I think chnlove never deletes a man's profile except in few examples such as David's so the total figure is so huge. But I think only chnlove headquater knows how much active members there are.
About DavidE's advice, chnlove would be very happy if whoever joins buy credits immediately but it doesn't help to eliminate scam admiration letters. Who send these letters are translators of agencies and they have no way to know if the target man has credits on his account. So I think Brett is right to say the huge number of inactive members is one reason for the extremely low responding rate. The other I think is the fierce competition among agencies.
Well, to be honest, with my limited experience of a single agency, I find that admiration letters are not very differently treated from cupid notes. I present that example of one lady who was frustrated in preparing admiration letters herself not to win your sympathy but to prove a word "inevitable". As I have said before, when ladies join this site through agencies, they usually pay a huge amount of overall fee unlike your clear investment in EMFs. Yet chnlove has a strict rule that agencies can charge nerve a penny from them for receiving, sending, and translating EMFs. So where do their fees come for? If an agency charges them such a huge fee and still ask them to write every admiration letter to every man they have interest in and decide whether to respond every cupid note yet give them no gurantee of positive response from men, will they still be willing to pay that fee? Sometimes ladies happily accept the service of "picking" the right one for them because they can enjoy the "fruit" without the hardship of plowing and weeding.