The Mail on Sunday says big companies are increasingly willing to fork out lucrative contracts to athletes who boast large numbers of social media followers and who are actively engaged with them. In addition, stars can also bank between £5,000 and £10,000 for any endorsed tweets they agree to post.
Rooney and his Manchester United team-mate Ferdinand are the most followed Premier League players on Twitter. Rooney has more than 5.2million followers and Ferdinand has 3.5m - larger audiences than some prime-time TV shows.
They have carefully cultivated their Twitter presence over several years, while the global popularity of United, particularly in Asia, has helped increase their followers.