The recent announcement from Adobe for NOT supporting CS3 on Snow Leopard had a massive impact on the web and leaded to major wave on complains. So, the company decided to publish a TechNote describing the list of problems spotted with CS3 on Snow Leopard: http://kb2.adobe.com/cps/512/cpsid_51215.html
There are not that many issues, but knowing them will help CS3 users to decide if it is worth purchasing the CS4 and Snow Leopard, or stay with CS3. If problems are now identified, Adobe (still) does not plan to release a fix/patch.