helenp - 11:54 am on May 31, 2013 (gmt 0)
It should be clear to your readers that this is a paid story by labeling it advertisement or sponsored story.
In some countries this is a legal requirement. Ignore it at your peril.
Does this apply to advertising online such as on google?
Well they do tell, in small letter and with a background color surrounding the ads, that only one knowing there should be ads can see, and with many dificults.
Honestly its there but not clear!