[niggler]

I suspect (not tested in this study) that the hyphenated version is seen as a possible fake if the unhyphenated version also exists. That is to say, face-book could be seen as fake because facebook exists, but a novel hyphenated phrase like vexing-sesquipedalian would not suffer the penalty because vexingsesquipedalian hasn't been used.

It would be tricky to test this, because you need to use a domain with hyphens where the original doesn't exist (and then you introduce new variables into the mix)

[eli]

I would think that in practice the overwhleming majority of hyphenated .com would also have an unhyphenated version (even if just a squatter)