Yahoo! (Nasdaq: YHOO) Finance has been a regular haunt of mine since I was but a wee Fool, and even before that. It has always been the most full-featured collection of free financial data available online, and the one-stop-shopping approach to data dumps is exactly what a stressed-out financial writer/analyst needs.

Others have tried and failed to make a mark on Yahoo!'s unassailable position. Microsoft (Nasdaq: MSFT) has MSN Money (even as the rest of its online portals have been rebranded under the Bing or Live banners), but I can never seem to find what I'm looking for there. I'm an online Wall Street Journal subscriber, but only read that site for the articles. WSJ parent News Corp (NYSE: NWS) also runs MarketWatch, where I find the sensory overload from obtrusive advertising a bit too much to bear. Even the official sites of market backers NYSE Euronext (NYSE: NYX) and Nasdaq OMX (Nasdaq: NDAQ) tend to pale in comparison to the homey familiarity found at Yahoo.

The list goes on. And Yahoo! beats them all, every time.

Who's that?
And then, there's Google (Nasdaq: GOOG) Finance. When it launched back in the spring of 2006, the site felt empty next to Yahoo!'s cornucopia of neatly organized information. I loved the handy, responsive, and quotable charts at first sight, and that feature alone kept me coming back to Google Finance whenever I needed a visual checkup of some share price or other. The rest was just a bunch of distractions -- Yahoo still had my heart and many others' as well.

But then Google Finance started to change, ever so slowly. Egged on by help forum comments and presumably some y emails, Google has been adding valuable features to its financial site while also taking the time to better organize the content you'd expect to find there.

Now Google Finance has a unique screener -- the same free, instant stock quotes you'll find everywhere else -- but Google's data keeps on ticking in pre- and aftermarket hours when Yahoo tends to shut it down. Its virtual portfolio management rivals the best, and you even get a bunch of imaginary indexes to track various aspects of the economy -- all based on analyzing Google's wealth of incoming search queries. All of this is wrapped in a visually pleasing skin and organized with simple but effective Web 2.0 menu selections. The company that built Gmail surely knows how to design a user interface for something as simple as a stock research resource.

What's new?
Now, Google Finance has filled one of the few remaining gaps in its financial service: tracking the value of stock options. The new option chain displays are thoroughly simple, showing nothing but the most basic information on puts and calls. Then again, that's all Yahoo Finance gives you nowadays, too. The Big Y used to throw Greeks and strangles and married puts at you on request, but now I have to go to my E*TRADE account if I want that kind of fine-grained options detail. Or, you know, take the call and put data from Google or Yahoo! and do the math by hand.

Google's options feature is by no means the most complete solution on the market, in other words, but it does stand up to Grandpa Yahoo and most of the other free fonts of information. The key takeaway here is that Google is actively trying to make this site competitive to the incumbents, and I believe that people are sitting up and taking notice. In time, Google Finance could move out of the Mountain View doghouse and sit next to well-respected services like Gmail, Search, and Google Apps at the dinner table.

The transition has already begun. Google Finance now shows up pretty close to the top of your search results if you Google a ticker -- or Bing it. You used to have to scroll down through oodles of irrelevantia to find it while Yahoo! Finance always did -- and still does -- come out on top nearly every time.

What's next?
I, for one, have started to gravitate toward Google Finance when researching my own articles, for reasons other than pulling a chart. In fact, I crawl back to Yahoo! for only two things: a firehose of relevant news feeds per ticker, and that handy collection of key statistics. Google's equivalents still leave me wishing for more. Maybe they'll fix these things too, one fine day. Yahoo still holds a crushing advantage over Google Finance in a much larger audience -- over 17 times the audience at last count from comScore, last December.

Can Google design its way into investors' hearts? I don't know, but the company sure is trying.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. Microsoft and Nasdaq OMX Group are Motley Fool Inside Value recommendations. Google and NYSE Euronext are Motley Fool Rule Breakers picks. Motley Fool Options has recommended a diagonal call position on Microsoft. Motley Fool Options has recommended writing covered calls on Nasdaq OMX Group. The Fool owns shares of Google. Try any of our Foolish newsletters today, free for 30 days. You can check out Anders' holdings and a concise bio if you like, and The Motley Fool is investors writing for investors.