It’s still not a word. Back in 2009, the people who write for yahoo.com tried to convince us that darkhorse was not just an album from Crazy Town, but an actual word. Three years later, they’re still trying to get us to accept the word:
Guess what. It’s not a word. You can repeat it again in three years and maybe by then it will be a word. But today, it’s just a misspelling.