Hi guys can you tell me why so many of the girls on the site will favorite you but not message you or
if you message them they never respond.  

Have had a small percentage message me first and it is usually good.

Thanks

They probably shoot out 10 million messages and then are bogged down in replies.

They can favorite a profile from the search results screen, without ever viewing your profile.  
.
My guess is that she creates a search based on her preferred criteria and she can see primary pic, ethnicity, age, location, body type, height, net worth and annual income on the results screen. She can then just go down the list and one-click favorite any profile she likes from the visible info, hoping that you will then message her in return.  IF you message her, she MAY read your profile, or just reply back to see if you will make her a quick offer.  
.
Try reducing your net worth and annual income to a very lowball value for a week and see if you get the same number of "blind" favorites.    If she (he?) can do any math, she will understand that any SD who makes $100k a year or less probably cannot afford an SB allowance more than $100-$200 per meet.  That could push the GPS SB's away, but may also keep the legit SBs from talking to you as well.. so experiment.  
.
As to why they may never respond... well there are any number of reasons:  
1. She found someone with a bugger... um wallet
2. She didn't like your message
3. She didn't like you
4. She never read your message. She only saw the 1st line in the message inbox view and didn't see the word or numbers she wants to see.  
5. She has a full dance card, and you're not on it.  
6. She farted just before reading your message then skipped it when she looked at her screen again.  
... you get the idea.  
.
Patience, patience, and patience. Just keep connecting and keep responding and eventually you will see that...
.
Life is good
.
The Cat