Performance
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This plugin generates static html files from your dynamic WordPress blog. After a html file is generated your webserver will serve that file instead of processing the comparatively heavier and more expensive WordPress PHP scripts. The static html files will be served to the vast majority of your users, but because a user's details are displayed in the comment form after they leave a comment those requests are handled by the legacy caching engine. Static files are served to: 99% of your visitors will be served static html files.
WP Super Cache « WordPress Plugins
Speed up WordPress on IIS 7.0 | RuslanY Blog
Since the time this article has been written the WP Super Cache plugin has changed a lot. I cannot guarantee at this point that the instructions below will work. Note that new caching plugins have been developed that support IIS better. I recommend to try out W3 Total Cache plugin which has support for IIS and WinCache. The performance of WordPress may be sufficient for an average blog that gets a few page hits per minute. However, if your blog post suddenly shows up on digg.com or any other social networking site, it may become challenging for server to handle such huge spike in traffic.
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