bitcoin has its own unicode code point, which is U+20BF. the corresponding unicode character is "₿"
however, this forum uses its own web font, which doesn't support that character! the consequence is that whenever I type the bitcoin symbol (₿) in a post on this forum, it's only displayed as an ugly square box, rather than the actual bitcoin symbol.
it is the responsibility of the website's maintainer to fix this issue by including the bitcoin symbol into the site's web font!