That's a big number for a premium software product. But of course, the beta is free, and the final version won't be, so it's hard to guess what the conversion rate will be from beta downloads to actual purchases.
Still, as a marketing stunt alone, it has to be useful for Adobe. Photoshop's price -- $699 for the full standard version and $999 for Extended -- is a big deterrent for people thinking about trying it. Getting it into people's hands could help convince them that it's worth paying for -- and perhaps that other software from the company's Creative Suite also is. It also could help encourage upgrades from people who skip alternate releases to save money.
Adobe hasn't had a public Photoshop beta since CS3.
New features in Photoshop CS6 include some areas of hardware acceleration, the arrival of video editing in the standard version, content-aware moving and patching that lets the software better fill in holes left by editing, better vector editing, new raw-image editing controls, selective blurring tools, an updated system for automatic image adjustments, an adaptive wide-angle tool to fiddle with perspective, and more.
The final version of Photoshop CS6 is due in the first half of the year.