factor is to return to our example of a user who has expressed a preference for non smokers but who may actually view and contact smokers as well as non smokers let us assume for purposes of example that our user has just signed up with our online service and has clicked on a single user profile before being pulled away from his or her computer to answer an incoming telephone call let us further assume the user profile viewed happened to be that of a smoker it turns out to be several hours before our user is able to return to the online service as our user logs in the question becomes how many smokers and non smokers should the matching engine select to display to the user based on our user 39 s viewing and contact history we see that our user has selected the profiles of smokers 100 of the time the one single click after signing up with our service it is undesirable to make a radical change in the selected set of user profiles to show only smokers on the basis of a single observation it is useful therefore to have an adaptability factor expressed as a number or a percentage.