Why do everybody use MSN, even if it is not safe enough?

I think the major reason of keep using MSN as the primary Instant Messenger is to follow the segmentation of MSN. As well know, MSN is segmented for businessman, and it is designed to use in offices on working time. Therefore, it is a business IM, not a entertainment IM. According to hte population of the IMs, only the users of MSN seem like "professional" in business. This is a psychological feeling, I think. In fact, any IM program can take place of it. However, people just FOLLOW, in order to behave like others do. Remember the song "Like humans do"? That might be a good example of the attitude of choosing the "business" Instant Messenger.