The Internet is primarily a communication tool. This is easy to forget in a web-browsing era. We should remember that the web was created only in 1990, while the first Internet email message was sent nearly 20 years before, in 1971. Exchanging messages via email, chat, or instant messaging, is the most important activity for the majority of Internet users. Communicating can be very important for a museum too. By using email, you can establish a direct relationship with your public. You collect important feedback from actual and potential visitors. Newsletters can strengthen this relationship. Professionals can be involved in discussion mailing lists about specific themes. Discussion forums and guestbooks can enliven a lot your website. Of course this is not for free; you have to dedicate much time to this activity. At the Science Museum of Milan we have used many of these communication tools: email, newsletters, forums, chat events, guestbooks, discussion mailing lists, online surveys, etc. Our aim was to create a sort of virtual community with our visitors. The paper will describe this effort, together with an evaluation of the results.