On Tuesday the search giant unveiled its Chrome Web browser, a bold move from a company better known for releasing useful if unfinished online services like Gmail and Google Docs than for producing mainstream downloadable software. (Google still labels both Gmail and Docs as “beta” projects, though they’ve been around for years.)

Expect Chrome to be held to a higher standard than Google’s previous efforts; after all, browsers are front-and-center for today’s Internet users, and we already know how they are supposed to work. Microsoft’s Internet Explorer, which has roughly 72 percent market share, is on its eighth version; Mozilla’s Firefox and Apple’s Safari are on their third.

Here’s the quick rundown on Chrome: Like every other major browser, it’s free. It’s marketed as fast and simple, much like Google’s search engine. The company also claims it is less crash-prone, more secure, and more search-friendly than competitors’. (It’s also less compatible; unlike Firefox and Safari, Chrome is Windows-only for now, though Google promises Mac and Linux versions soon.)

Early reviews are mixed; on TechCrunch, Don Reisinger calls Chrome “one of the fastest” browsers he has used, but Walt Mossberg at AllThingsD says it launched Web pages more slowly than Firefox and Safari in his tests.

For Google, Chrome’s release offers both risks and rewards. Among the risks: that the company has too many balls in the air. Two years ago, with Google stock trading in the mid-$400 range, executives began trumpeting the slogan “features not products,” saying employees had taken on more projects than they could manage well.

But over the past few months we’ve seen Google launch Google Health for online medical records, now its Chrome browser for PCs, and soon its Android operating system for mobile phones – some of its biggest products ever – and the stock is back in the mid-$400s. With Google juggling all that, there’s a real risk that something will slip.

But Google is betting that Chrome’s potential rewards are worth it. With its own on-ramp to the Internet, Google can now make a far more compelling case for its vision of the future, where ad-supported Web-based services replace old-school software like Microsoft Office.

Now, rather than wait for Microsoft, Mozilla and Apple to speed up their browsers, Google can turbo-charge its services through Chrome and dare them to catch up. (Plus, as Google expands onto phones and other devices – a key element in the company’s growth strategy – homegrown browser technology will allow the company to keep its user experience consistent.)

There’s also a defensive element to Chrome. After all, you need a browser to access most Google services, and the biggest browser maker in the world is also Google’s mortal enemy with no incentive to tailor Internet Explorer to suit Google’s needs. Apple is focused on Macs, iPods and iPhones more than on online services. Mozilla, whose Firefox browser has taken share from IE, has been a strong partner – but given the stakes, it makes sense for Google to have more control over which features get added to a browser, and how quickly.

Of course, none of this matters much unless Web surfers flock to Chrome – and success may be elusive. Unlike IE and Safari, which are bundled with the Windows and Mac operating systems, Chrome doesn’t come with a ready-made distribution system. And unlike Firefox, which has gained critical mass after years of trying, Chrome is just getting started.

Even if Chrome gains market share, it could end up being a mixed blessing if it comes at the expense of Safari and Firefox. After all, though Apple and Mozilla have slightly different priorities than Google, all three share the goal of keeping Microsoft from getting too much power in the browser wars.

So is Chrome a good idea? A year from now if Google is #3 or better in the browser rankings and Microsoft has lost share, perhaps. But if any of Google’s other major projects have slipped along the way, investors may look at Chrome as just the latest shiny object to distract the search giant.