From the JSLabs blog today comes a helpful tip for those running a WordPress blog that might be taking a beating - like from being linked on digg.
This is usually caused by a large amount of traffic that is overloading your database (because each page that is loaded requires a query or multiple queries). A great way to not only improve the speed of your entire blog, but help prevent the above error from occurring is to install a plugin called WP-Cache.
The WP-Cache plugin automatically caches your pages without the need to install any outside methods. The post steps through how to get it installed and how to