Wall mounting a flat-panel TV This Old Nerd (SD)

Time to get the home theater re-started! The #1 thing on our list was wall mounting our new HDTV. However, we got a couple of professionals to install the TV and give us some insights on what you should know if you want to attempt this yourself.
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Note: Other downloadable versions are coming soon. Changes to our preferred hosting services will delay downloads of the HD (mp4) and SD versions.