Metric. Not disappointed but I would never have guessed it.
Text surrounded by asterisks (*) is italicized.
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Symbols such as *, +, |, and ~ can be used literally by placed a \ in front of the text.
A user's name surrounded by at signs (@) links to their profile, and the user is notified that you mentioned them.
A word surrounded by hash signs (#) becomes a tag and links to posts with that tag.
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URLs become links. However, new users cannot post links in comments.
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Image URLs (.png, .tif, .gif, and .jpg) will embed automatically.