But they did work.

Nine years after it was made, Apple’s first uncertain leap into retail has proven a master stroke. Discussing the company’s second quarter earnings on a recent conference call, CFO Peter Oppenheimer noted that revenue from Apple retail stores was $1.68 billion — up from $1.38 billion in the same period last year, and that they sold 606,000 Macs, significantly more than the 438,000 they sold a year earlier.

And half of those were sold were to customers who had never owned a Mac before. Clearly, Apple’s stores have played a pivotal role in attracting new users to the Mac platform — particularly those who use Microsoft (MSFT) Windows. As Needham and Co. analyst Charlie Wolfe noted in a research bulletin to clients this morning, the Apple Store has proven a real magnet for PC-to-Mac switchers.

“Along with the halo effect emanating from the iPod and iPhone, the Apple Stores themselves are playing a pivotal role in attracting Windows users to the Mac platform,” Wolfe wrote. “We estimate that since 2004, over 18 million Windows users have switched to a Mac, equal to over 100 percent of the total size of the Mac platform at the beginning of this period. Reflecting this, Mac sales in the March quarter were almost four times higher than they were in the second quarter of fiscal 2004. Windows switchers, then, have more than doubled the size of the Mac’s installed base. … We estimate that Windows visitors represented well over half of the 170 million visitors to the stores in fiscal 2009.”

A metric worth considering in light of Apple’s big retail plans. The company has said it hopes to add between 40 and 50 new stores to the 286 it already has opened this year alone. Will another big surge in the size of the Mac community follow?