Today many online services have a membership or paid subscription-based model. News Portals often use them to subsidise their profits, making up for loss of revenue from decreasing physical paper sales. Recruitment sites use membership as a way of tailoring a member's job search requirements using filters. All websites that ask you to register use the information provided for marketing purposes, which depending on the content the member may or may not find of interest. But the best companies don't just use their membership base to sell… they use it to inform.