Revealed: Google's biggest advertiser is the University of Phoenix spending nearly $200,000 every day

Being the world's most popular search engine, Google might seem like the ideal venue for advertising from big business. But the web giant's biggest advertiser is not in fact a multinational company, but a university.



The private, for-profit University of Phoenix was Google's top customer over the last quarter, beating finance and retail firms as it spent nearly $200,000 a day on AdWords.



The surprising revelation came as an analyst claimed that Google had enjoyed record success in its ad sales, with over $100million coming in every day despite a fall in how much companies are willing to pay for each ad.



Google's advertising revenues have risen 15 per cent on the previous quarter

The research by WordStream , an internet advertising firm, put Phoenix at the head of the list of Google's most lucrative customers.



The university, which specialises in courses aimed at unconventional students such as older people, advertises heavily on television as well as online.



Second in the list of Google's top advertisers is Ask.com - a search engine which is one of the company's biggest commercial rivals, but which nonetheless pays $155,000 a day to advertise on the site.



Amazon, another firm which challenges Google for the title of the web's biggest giant, spent $132,000 on AdWords in the third quarter of 2012.

AdWords is the system which controls ads both on Google's own search pages and on other sites which sign up to partner the firm.



Despite its wide network of online services, from news to translations to mapping, over 90 per cent of Google's revenues come from advertising.



So the firm will be reassured by WordStream's conclusion that its advertising revenues have risen by more than 15 per cent compared to the previous quarter.



It was previously revealed that the amount advertisers are willing to pay per click had tumbled by nearly 20 per cent, a statistic which caused Google's share price to crash when it became public.



But the still-growing number of ads appearing on the site means that the business is still expanding.



Overall, finance is the sector which is most likely to advertise on Google, with firms such as State Farm, Geico and Bank of America all important customers.



Travel comes second, as companies including Expedia and Priceline plough millions into attracting vacationers through Google.



In total, there are 5billion ad impressions on Google every day worldwide - nearly one for every human alive.



