Most of my website forms have specific questions for buyers or sellers , therefore when I answer the email I have a good idea what they are looking for or what they need.
EXAMPLE
For buyers I introduce myself in my first email and let them know I will be sending them listings that fit their criteria, and to contact me if anything interests them. My MLS has a prospecting program that I enter the user information which automatically sends them listings. I usually follow up with one more email and if I haven't heard back from them yet I move on. I allow the MLS prospecting program to continue sending them listings just in case, if they see something they like they will contact me.
I noticed your buyers forms only have; Name, Email, Phone, and Comment. Why not get more specific about what they might want, so when you contact them you don't have to ask them a bunch of questions. You could just start sending them listings.