Why do certain lines within emails become underlined when received in yahoo?

[Nation150_Rizzo]

Why do certain lines within emails become underlined when received in yahoo?
It only happen's in Yahoo, no other email service.

[Anonymous]

You can also test your emails using Litmus to see what the emails will look like before your send them. It is one of my favorite tools.

[Anonymous]

I think those are what they call Yahoo Shortcuts.  Should just be actionable info, like phone#'s, locations, email addys, and if you hover over them I think it will give you a shortcut menu for various stuff yahoo might be able to do with such info.
Basically just yahoo gunk messin' up your work.