help me thinking... What big companies whant to buy online?

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well i was thinking in give some uze to my coding and webdesign skills, and i started thinking in what do big companies may buy online? one of the things that ocurred to me was, they need emails to sent pub and get clients, or... i cant think at nothing else for now.. My ideia was to find out something that gives profit and kinda make a site to get those resources, kinda pay to click sites or others that make lists of emails, i whant to create something new and helpfull for mutch others that whant to make some extra money with few time :) try to give me some ideias, maybe something comes out of this