On SEO Impediments

An interesting thread is taking place at V7N titled SEO Impediments. It proves the notion that this guy presented as wrong and shows that there are very many who don’t know their left from their right when it comes to SEO.

The thread starts with the top 5:

1. (Poorly designed) doorway pages
2. Keyword stuffing
3. Non-SE-indexable site navigation
4. Robots.txt exclusions
5. Duplicate content causing pages to go supplemental

and continues with many more (check post for entire list).

Do you know of any such impediments which are totally wrong?