I've just discovered that the answer I had given on EL&U was missing something. When I pressed the edit button, I saw that I had written a V and enclosed in < and > i.e. < v > (without spaces) but it just wouldn't show up. It's not showing up here either -> (press edit to see)
I had written <v> but when I submitted the answer, the 'v' didn't show up in the answer. It was fine back then. Is there something wrong with the formatting? Am I formatting it incorrectly?
The system is interpreting <v> as an HTML tag, and therefore it's not shown. Not all HTML tags are supported, but e.g. <b>, to make things bold, works:
<b>test</b>
produces
test
Notice that the tags seem to have gone here as well, but in this case they do have an effect. For a list of supported tags, see What HTML tags are allowed on Stack Exchange sites? on Meta Stack Exchange. This may indeed be rather confusing.
It is possible to use <v> in regular text, if you replace the opening < with its HTML entity < (or > with >).