Google penguin is Google algo update launched in April 2012. The update is aimed at decreasing search engine rankings of websites that violate Google's Webmaster Guideline.
There is difference between methods and type of SEO.
There are two methods of doing SEO
1. On page Optimization
2. Off Page Optimization
There are three types of SEO
1. Black Hat SEO
2. White Hat SEO
3. Grey Hat SEO
Keyword stuffing is the black hat technique to boost the web page ranking. In this practice keywords or phrases are stuffed on the various positions on the web page like title tag, meta description, heading tags as well as in content.
Link pyramids are a revolutionary strategy that exploits the binding factor of Web 2.0 authority sites. From quality links below basic level, a link connecting funnels power pyramid at level 1 of the pyramid which then links to your site.
You can search on Google you will find lots of resources providing the .Gov and .edu backlinks. This links are so powerful and boost your rank on search engine result page.