If you checked out Fool.com over the Memorial Day weekend, you probably caught Tim Beyers and myself sparring over growth stocks.

If you'll pardon the bravado, I can actually just let Tim argue my own pro-Amazon case.

"Amazon is almost 10 times bigger than Akamai," Tim writes. A paragraph later, he adds, "Amazon is bringing in close to $20 billion a year in revenue, versus less than $1 billion for Akamai."

In other words, Akamai is trading at a loftier price-to-revenue multiple than the world's leading online retailer. Akamai's P/E ratio is admittedly lower, but we know which way margins are heading at the content-delivery network giant. Analysts see revenue growing faster than earnings per share at Akamai in both 2009 and 2010. Wall Street sees Amazon's margins widening next year.

Of course! Akamai faces a future of "me too" competitors eating away at its pricing power. Akamai's biggest customers may also be tempted to create in-house solutions.

Amazon, on the other hand, has vanquished its rivals, and it's sailing smoothly toward digital delivery and the high-margin promise of the Kindle Store ecosystem. Online retailers are either specializing in niche categories -- like Blue Nile (NASDAQ:NILE) for jewelry or Drugstore.com (NASDAQ:DSCM) for pharmacy goods -- or just clearing out of Amazon's way.

Bigger doesn't mean slower
"Akamai should double up on adding roughly $900 million in new revenue," Tim argues. "Amazon, at its present multiple, would need $20 billion in new sales to achieve the same result."

That's a common argument. Conceptually, it seems easier for a smaller company to double in size. Small-cap investors feast on this. So do penny stock investors, figuring that stocks like Sirius XM Radio (NASDAQ:SIRI) or Blockbuster (NASDAQ:BBI), which trade for pocket change, have greater potential upside than Google (NASDAQ:GOOG) at nearly $400 a share. The volatility is certainly greater for companies earlier in their growth cycles, but who's charting Amazon's growth relative to Akamai's?

Let's take a look at earnings. As I noted on Friday, Akamai's net income is projected to grow by just 2% this year, and 5% next year. Amazon, on the other hand, is looking at a 9% bottom-line boost this year, and a 26% push in 2010. In other words, by the end of next year, Amazon will have to grow earnings by just 45% to double the $1.49 a share it earned last year. Akamai's profits would have to jump 85% to post a similar multiple of gains.

Sorry, Tim. I can certainly appreciate Akamai's role as a pioneer and a market leader in a very important industry, but Amazon is the superior growth stock.

Other headlines, if you still want to live in the past:

Akamai Technologies, Google, and Blue Nile are Motley Fool Rule Breakers selections. Amazon.com is a Motley Fool Stock Advisor selection. Try any of our Foolish newsletter services free for 30 days.

Longtime Fool contributor Rick Munarriz has been shopping online for about as long as Amazon.com has been in business. He does not own shares in any of the stocks in this article. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.