I think that this is not really a very good thought because the people will start misusing the contact import feature and this may result into the emails falling in the spam. With my experience i can say that if people start sending emails more frequently then the emails would be falling into the span folder of the email which will never help for bringing more people to this website.
I would suggest that we should be keen on providing contest and should give away some money on frequent basis for bringing more traffic to this website.
Today in the internet age, people very frequently visits the blog directories, We should also submit links to the blogs directory so that more people come across them and visit this website. this will definitely work in increasing the traffic to the website.