Question about my yahoo email.....?

NEED HELP WITH YAHOO E-MAIL.....Can someone help ??......When I send a email through yahoo....I go back to "Sent" mail to make sure of what i sent & some words are highlighted in BLUE and UNDERLINED (Usually.... dates, times, days & locations) everything else is ok and in black).......Anyone know why this is ?...I'm trying to not have these highlighted in a different font & underlined.....how do i get rid of it ??