Google just unveiled Google Finance aimed at private investors. The new service correlates stock quotes, trading volume, executive bios and information, top news, blog posts, and Google-hosted moderated message boards. Check out the information page for GOOG for example.
The site uses Flash technology to create interactive graphs. You can hover over any data point on the graph for more information and adjust a date-range slider beyond the default 3-day view.
Blog data from Google Blog Search appears above message board content for selected blog. Given the frequent posts about a given company it makes sense to filter the results to avoid too much noise and Google seems to be filtering by the total number of source links or some other authority metric to determine inclusion in the results. There are three featured blog posts on the Apple Computer page pulled from the last week for example.
My favorite feature is the stock charts with major news stories, price data, and trading volume all overlaid in the same view. You can even drag the chart to the right or left to see more data!