Which one of the following practice is ethical?
A. Buying links from link farms
B.Stuffing the metatags with keywords
C.Having the same page twice - once in html, once in pdf
D.Using hidden text that users do not see but spiders can read
A. Buying links from link farms
B.Stuffing the metatags with keywords
C.Having the same page twice - once in html, once in pdf
D.Using hidden text that users do not see but spiders can read