Quote Originally Posted by Sinan
Applied to humans, it's the same.
No, there is a crucial distinction between them: Darwinism explains what happens, Social Darwinism justifies it as what should happen. One is factual (though disproved and updated over time) and makes no moral judgments; another claims to be morally correct.

If I am to provide an answer now, I would say I find Darwinism to be a historically important step towards modern biology, possibly the most important step; on the other hand I find Social Darwinism to be a morally abhorrent ideology.

Or to put it in a historical perspective: Darwin himself was a devout Christian and did not try to apply his theories to society or give them moral values. It was the work of others that do so -- example, Herbert Spencer, who coined the infamous term "survival of the fittest."