This application of Chartoon shows the market capitalization of some major internet companies. The data is always up-to-date as it is loaded each time when you display the page from Yahoo Finance. And if the page is not reloaded for more than 24 hours the chart refreshes the data itself.
And with the same data feed you can create other views. This pie chart shows the same data as the bar chart above. But honestly, it looks a bit crowded.