Buying Links

[Jason76]

Search engines don't like it and will harshly penalize, but it's not illegal according to the law.

Anyway, guest posting is often a paid transaction and so are directory backlinks. Are there exceptions?

 

[Nomad]

You can also pay people to use your link as a forum signature, this is also a paid backlink. You can use forums that offer paid backlink services. Technically speaking, Google cannot find out whether the backlink is organic or paid, so you are good to use it.