idolw - 9:24 am on Jun 16, 2010 (gmt 0)
Black hat is simply manipulating the search engine results pages using a number of methods including:
- hidden text and hidden links;
- cloaking - described above as showing one page version to engines and another version to real users;
- taking part in link schemes, especially automated;
- using doorway pages, i.e. pages built only to set up a cookie on user's computer
In general... anything that looks dodgy at first sight.