I had this too - lots of random words underlined and leading to advertising links. Turns out the most recent update I did of Mozilla had this attached to it - but it was easily located in my Programs (as Yontuu) and is gone now....I think!!
To celebrate the super release of the action packed, family adventure Barbie in Princess Power, available on Blu-ray?, DVD & Digital with Ultraviolet? from March 19, we're giving one lucky parent the chance to win the entire collection of Barbie DVDs and a Barbie Super Sparkle Doll.