When I surf the web, I almost always have Fiddler running, and as a consequence I see a lot of “hidden” pollution in pages. Much of this cruft has built up over the years, copied from site to site, probably with little critical thought about its necessity.
Please remove any META tags you have that specify MSSmartTagsPreventParsing. This directive only ever had any effect in an IE6 Beta, and the feature in question never shipped in a final version of the browser. Sending this directive is a waste of bandwidth.
Next, META tags that specify imagetoolbar should probably be removed. This META disables the IE6-era Gallery Toolbar that showed atop images of a certain size; that toolbar was removed in IE7. Similarly, the galleryimg attribute on IMG tags is generally not needed for the same reason.
In nearly all cases, sites that send the pre-check and post-check directives in the Cache-Control HTTP Response header should remove these directives. These directives only ever worked in Desktop IE browsers, and they almost always are sent as part of a long string of no-cache directives (PHP unnecessarily sent these directives when a page was not to be cached). Sending these directives when you’re using other directives to forbid caching is a waste of bandwidth.