Why Sedo do this?

[Domain123]

Sedo add such code for some parked domain name and make it not searchable. (Parking page source code)

<iframe width="1" height="1" marginwidth="0" marginheight="0" hspace="0" vspace="0" frameborder="0" scrolling="no" src="http://pbid.pro-market.net/engine?site=108356+size=1x1+kw=**** ***"></iframe>

**** *** is the domain parking keyword

pro-market.net is also Under Construction.

Why that's code let domain lost all traffic?

Please sharing your knowledge.

Thanks,

Bill