10 Ethical black hat SEO techniques

1. Hidden text – Create modern CSS based websites with JQuery effects. They often hide large portions of text in layers to display them on click or mouse over for usability reasons. Example: CSS pagination.
2. IP delivery – Offer the proper localized content to those coming from a country specific IP address. Offer the user a choice though. Shopping.com does a great job here.
3. 301 redirects – Redirect outdated pages to the newer versions or your homepage. When moving to a new domain use them of course as well.
4. Throw Away Domains – Create exact match micro sites for short term popular keywords and abandon them when the trend subsides. Something like tigerwoodssexrehab.com
5. Cloaking – Hide the heavy Flash animations from Google, show the text-only version optimized for accessibility and findability.
6. Paid links – Donate for charity, software developers etc. Many of them display links to those who donate.
7. Keyword stuffing – Tags and folksonomy. Keyword stuff but adding several tags or let your users do the dirty work via UGC tagging (folksonomy) every major social site does that.
8. Automatically generated keyword pages – Some shopping search engines create pages from each Google search query and assign the appropriate products to each query. You can do that as well if you have enough content.
9. Mispsellings – Define, correct the misspelled term and/or redirect to the correct version.
10. Scraping – Create mirrors for popular sites. Offer them to the respective webmasters. Most will be glad to pay less.