Ethical search engine optimisation, in short, is to follow guidelines and accepted standards to search engine optimise a website. This means we don't use any tricks or cheats that are sometime employed by "Black Hat" practitioners. The end result of ethical SEO is a stronger positioning that is much longer lasting, and can withstand frequent changes made to algorithms.

Black Hat optimisation on the other hand, uses optimisation strategies that can sometimes result in faster results, but are rarely long lived. Some Black Hat strategies can result in being penalized, or even permanently banned by some major search engines and directories.

Ethical optimisation is the only way to go; don't run the risk of having your site banned.