This CNNMoney article
has an interesting look at Yodlee, especially in the business aspects. Here's an excerpt that shows how widespread Yodlee is:
If you've banked online, you've probably used Yodlee without even knowing it. More than 200 financial institutions, including Citibank and Bank of America use its services, touching nearly 26 million consumers.
Much of Mint.com's success was based on Yodlee. However, according to the article, Mint.com is switching its account aggregation system from Yodlee to Intuit.