.NET SP1 Can Break HttpWebRequest (and certain RSS Feeds)
If you installed SP1 for the .NET framework, you may notice that certain feeds are broken and return an HTTP Protocol Error. Dare looked into this and posted an explanation and workaround to the problem.
Apparently a lot of web servers out there are a bit loose with the HTTP specification while SP1 tightens compliance. So c'mon people, stick the chest out, shoulders back, stand up straight, and stick closely to the spec.