You can change the size and type of your IM font to suit you. This is a useful option if you’re having trouble reading the default font. Find out how to change your IM font.
You can also use some basic formatting in your instant messages to make them more interesting.
Italics
Put _underscores_ around the words you want to emphasize.
Bold
Put *asterisks* around the words you want to make bold.
Strikethrough
Bookend your text with ~tildes~ to put a strike through it. You might use this to convey sarcasm or show what’s changed, for example.
Monospace
For that plain text look, wrap {code} around words like this:
{code}This will be monospaced{code}.
To send your entire IM in monospace font, start the message with two exclamation marks and a space (!! ).
Override special formatting
Put two @ symbols and a space (@@ ) at the beginning of a message to prevent special formatting. You can also switch off formatting in your IM settings. You’ll still see other people’s formatting; you just won’t send any.