Except they don't. I have a one-word legal name and I have rarely found any online from that allowed me to have less than two names. I realize I'm an edge case, so I just make up something for the other field.
Ironically, I practically begged Google+ to allow me to use my real name, which they require for their "fine dining experience" (<cough>advertisers<cough>), but they refused because it was less than two names and looked fake. They may have finally worked that out by now, I left the building long ago.
Except they don't. I have a one-word legal name and I have rarely found any online from that allowed me to have less than two names. I realize I'm an edge case, so I just make up something for the other field.
Ironically, I practically begged Google+ to allow me to use my real name, which they require for their "fine dining experience" (<cough>advertisers<cough>), but they refused because it was less than two names and looked fake. They may have finally worked that out by now, I left the building long ago.