Definition of Blackhat SEO

[Bruno]

I have read a lot about it, but i have never try anything from that perspective, that's just not for me, but i keep getting questions about it and i see that a lot of people have wrong definition of Blackhat SEO.

Example, is search engine submissions blackhat SEO? To me that's just stupid service which most of "SEO" companies charge. Is hidden text BH SEO? or some stuff like that? To me that's not SEO at all, that's just ignorance.

Can you give me definition of BH SEO? What tactics most of BH SEO use? Any articles about it, links?