I removed all IM icons in the posts, as well as in the "edit user profile" page. All of them except skype are already past (dead or no longer used by most of the people).
I don't know how to add new fields (such as facebook/twitter/youtube/linkedin/whatsapp/hangouts) to vbulletin though. Looks like there is a plugin but only paid vbulletin customers can access it
