And speaking of Google's Web Accelerator, besides privacy issues, there are some rather problematic issues with web applications. The guys at 37Signals happened to catch them very quickly because they have their noses sticked to their Backpack servers logs right now, but Google should correct that behavior soon because you can't expect every site to clean after issues in this tool. And correcting bugs in a desktop application isn't as fast as fixing a web application, you have to get all those users to upgrade.
Oh, and that reminds me of the fears that RSS aggregators would "kill the web" by being bandwidth hogs. What would you say of an application that just sucks every link it can find on a web page just to save you a few seconds here and there? Is Google going to sell bandwidth anytime soon?