Amazon's ad business makes twitter's IPO look puny

Twitter is an advertising business. And with its upcoming IPO, the company is on a mission to convince Wall Street that it can attract big-name brands like a magnet.

Meanwhile, Amazon is the world's largest online retailer. But on the side, it does ads too, plastering them on its retail site as well as an online network of partner sites.

According to research firm eMarketer, which specialises in analysing online buying and selling, Twitter will likely bring in just under $583 million in ad revenue this year. That's more than double what eMarketer believes Twitter brought in last year, but the research firm says Amazon will likely pull in $840 million. Ad revenue for the e-commerce giant was up 45% over 2011's earnings. Strong and consistent growth in the company's ad revenue is expected in the coming years. Amazon's ad revenue in the U.S. alone is expected to reach $1.1 billion by 2015.

To get an idea of how Amazon’s ad business compares with some of today’s biggest players, here are the full-year 2012 ad revenues for Google, Facebook, Yahoo, AOL and Twitter:

·         Google: $43.7 billion

·         Facebook: $4.28 billion

·         Yahoo: $4.03 billion

·         AOL: $1.42 billion

·         Twitter: $288.2 million (per eMarketer estimates)

Amazon has a vast stockpile of data and significant audience and clearly advertiser interest. But it’s unclear at this point how aggressive they plan to be about advertising.