Tell me a few Black Hat SEO techniques?

[houdini]

I know BlackHatSeo is bad but effective, so please tell me a few name of Black Hat SEO techniques?

[addpronetworkpvtltd]

Hi,
Black Hat SEO Indeed is a bad technique in Search Engine Optimization.
Some of them are as follows
1) Spam Comments
2) Paid Back links
3) Duplicate Contents
4) Keywords Stuffing
etc
The content or websites should be user friendly.