from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any website that allows users to upload content, particularly YouTube itself.
- n. A small video that can be viewed online, particularly one hosted on YouTube.
- proper n. A video-sharing website.
- v. To upload a video of something to YouTube.
you + tube (North American colloquial term for "television"), implying that users (the "you" in the title) may submit their own television (the "tube" in the title) content. Perhaps some humor was intended due to the slant rhyme with the popular slang term boob tube. From the name of http://www.youtube.com/ a popular website allowing users to upload videos. (Wiktionary)