yellow
The conclusion of an excellent rant about the appearance of IntelliTXT advertising links in online news articles:
The in-text ad links have a slightly different appearance than the legitimate news-content link supplied by the columnist herself. The advertising links are underlined in green text. The news link is not underlined and it's in blue text.
This is what the distinction between news content and advertising has come down to: the difference between blue and green. I suppose this is what they mean by "yellow journalism."