Google Finance offers most of the features already offered by Yahoo Finance. It even offers some unique features, such as interactive charts and company-related blogs. But are they enough to dethrone Yahoo Finance, the most popular finance website ? Read this comparison GOOG vs YHOO

The obvious URL
yahoo.com/finance returns a 404 while google.com/finance takes you to Google Finance portal.
Yahoo should be smart here and redirect users to finance.yahoo.com.
When you type finance.google.com, Google redirects to finance.google.com/finance - Why that extra finance after the subdomain ?

Front Page
Google has no ads. If you have signed in with a Google account, you will see stock quotes and news related to your recent searches. These section remain hidden if you there's no search history.
Yahoo Finance front page has ads at acceptable locations. More information is available like currency exchange rates, mortgage rates and links to finance related websites arranged in categories.

Stock Quote Search
Yahoo Finance requires you to remember the exact ticker symbol. Though there's a Yahoo Symbol lookup table, I think it should be integrated with primary stock search. The Yahoo Stock Screener lets you find stocks based on criteria like industry, share prices and other data.

Google Finance is smart. If you enter name of a company, even in part, Google does a "I'm feeling luck" search and takes you to the associated Stock information page. If Google doesn't find the stock company, it shows the resuls from Companies and Funds for you to choose from.

Google Finance has an integrated screener though not as advanced as Yahoo. You can enter an industry like "Magazine" and Google shows a list of companies associated with the Magazine publishing industry.

Stock Charts and other Information
The Google Finance page for Adobe looks really ugly on my Widescreen notebook. The "Flash" stock chart is too huge and occupies more than half the width of the screen. Yahoo has a much cleaner interface and looks more professional.

Google uses lot of Ajax and Flash, you can see stock quotes between custom dates with refreshing your page (like GMail or Google Maps). Then there a previews of Company Executive pictures, Links to related companies (or competitors).

Yahoo offers a more traditional look, the stock related information like Company profile, Balance Sheet, etc are all neatly arranged in the sidebar which I think is a better approach that Google finance. If I am check Adobe Stock several times a day, would I be interested in seeing the picture of Bruce Chizen each time ?

Blogs and Forum Posts
Google shows related blog posts. It essentially searches for the company name using Google Blogsearch and displays the top three results. This is of little or no significance as the posts can be misleading. While looking at the Adobe stock page, I could see a blog post selling pirated Adobe software. This is bad example considering that typically high-income, well-educated adults visit Finance websites.

The forum posts (Google groups discussions) are relatively better since they are moderated by Google staff. So it becomes difficult to flame Google in these forums.

Conclusion
There is already news that Yahoo is revamping the Yahoo Finance portal with new information, multimedia, and style features. Yahoo plans to make stock charts more dynamic and will incorporate sound, motion and video in the site.

Google Finance portal will prevent Google visitors from going elsewhere. Google has definitely made a good start but the Google finance portal interface requires serious tweakiing. Teenagers and hardcore geeks are not the usual kind of people that visit Finance portals. Elderly people who are not very computer savvy consitute the bulk of traffic on Finance websites. Heavy use of Flash or AJAX may just turn them off.