Etsy, an online marketplace for craft creators and sellers, is now worth $300 million, TechCrunch reports. It's the latest in a series of fundings of platforms built from Web technologies.

Color me unsurprised. Platforms have several advantages. The biggest? Profits. Customers tend not to abandon platforms that help them make money. In Etsy's case, top-selling craftspeople are like the power sellers who keep relevant eBay's (Nasdaq: EBAY) aging-yet-enduring marketplace.

What should encourage you as an investor is that there are numerous investment-worthy platforms whose stocks trade on the public markets, many of which are growing at a brisk pace. Here's a closer look at three of my favorites.

Amazon.com (Nasdaq: AMZN). A platform for platforms, Amazon Web Services adds heft to popular services such as Twitter. It's also a big and growing business for the e-tailer. Earlier this month, UBS Investment Research analysts Brian Pitz and Brian Fitzgerald estimated AWS' 2010 revenue at $500 million, growing to $750 million next year and $2.54 billion by 2014, GigaOM reports.

Google (Nasdaq: GOOG). The Big G makes a habit of delivering services from the cloud, some of which have proven essential. Gmail has at least 100 million users, and Google News has become so important that Rupert Murdoch had made it News Corp.'s (Nasdaq: NWS) Public Enemy No. 1.

salesforce.com (NYSE: CRM). Developers and customers can't seem to get enough of this cloud-based business software platform. There are now 940 apps in AppExchange, a marketplace for software that adds functionality to the underlying system. More than 20,000 of its customers use its Chatter collaboration tool, CEO Marc Benioff said in announcing earnings recently.

Though I like all three of these stocks, I've recommended both Google and salesforce.com to our Motley Fool Rule Breakers subscribers. I'm inclined to take either one over Amazon.

Choosing between Google and salesforce.com is more difficult, but I'll take The Big G. Why? Valuation. Much as I continue to believe in salesforce as a multibagger, it's simply unreasonable to value a fast grower such as Google at less than 15 times next year's earnings -- especially when Wall Street has a history of underestimating Google's earnings power.

Now it's your turn to weigh in. Should Google make our list of 11 o'clock stocks? Let the debate begin in the comments box below, and when you're done, click here to get today's 11 o'clock portfolio pick.