Google recently launched their finance page. The graph below tracks mentions of both Yahoo and Google finance both in terms of URLs and by terms. Note that Google serves the page both as finance.google.com and google.com/finance. However, the second version is not as popular as the first.
What this graph suggests is that citations of Yahoo's page seem pretty constant in the URL space (the yellow line along the bottom). Google's page got a big hit at launch but has since dropped down below Yahoo's baseline. Mentions of Yahoo's page (the green) appear more erratic with a possible downwards trend - though this could be an artifact of certain types of growth in the blogosphere.