On August 28, 2009, it was released worldwide, and was made available for purchase from Apple's website and its retail stores at the price of US for a single-user license.
As a result of the low price, initial sales of Snow Leopard were significantly higher than that of its predecessors.
I've got three 10.6 computers that won't install OS X updates.
Checking for new software will show about a dozen updates (Security updates, Safari, i Photo, printers, etc) and if choose install it downloads them.
The release of Snow Leopard came nearly two years after the introduction of Mac OS X Leopard, the second longest time span between successive Mac OS X releases (the time span between Tiger and Leopard was the longest).
Unlike those of previous versions of Mac OS X, the goals of Snow Leopard were improved performance, greater efficiency and the reduction of its overall memory footprint.
If you're using a Mac with OS X 10.5 (Leopard) or older, you must first purchase a copy of OS X 10.6 (Snow Leopard) and install it on your Mac before you'll be able to update Safari.
Apple recently released a new version of its Mac operating system, mac OS Sierra (version 10.12).
With the release of Sierra, Apple decided to drop support for some Mac models that were supported by several previous releases of the Mac operating system.
How far you choose to upgrade your Mac is entirely up to you.
But it's definitely time to get things in order, because there are good reasons why you're getting the "This version of Safari is no longer supported", and they typically have to do with security or capabilities that you're missing. It works fine but I keep getting messages that says "This version of Safari is no longer supported. I also can't download certain programs or open some You Tube videos.