fascism favours corporatism and the left doesn't. fascism is usually extreme-nationalism and the left isn't. fascism is totalitarian and most people on the left are anti-totalitarian. fascism is anti-rationalism and the left isn't. fascism is patriarchal and the left is not (or at least shouldn't be) fascism is also often racist and homosexual and the left is not.
so, in short, they are idealogical opposites....
........................................Fascism... ..........Socialism
Nationalism..........................Yes.......... .........No
Totalitarian..........................Yes......... ..........No
Rationalism............................No......... ...........Yes
Patriarchal............................Yes........ ...........No
Racism/Homosexual...............Yes..................No
Democratic............................No.......... ..........Yes(well hopefully, although some views of some people on here scare me)
"There is no other definition of socialism valid for us than that of the abolition of the exploitation of man by man" - Ernesto Che Guevara
'The Great World Power Has Not Yet Found The Weapon To Destroy Dreams' Subcomandante Marcos
'Freedom without Socialism is privilege and injustice, and that Socialism without freedom is slavery and brutality.'