If you want to find people who wants to advertise your project go to Service and post what you are looking for and you will get more responses than sending PM to every random users, if you want to hire any specific user you can PM them and since you are a new user there will be restriction in the number of PM you can send, if you look at the service section you can find many people advertising their service, you can contact them rather than sending mass PM. Hope you got the answer what you are looking for.