I know Vocaloid is a signing synthesizer software but while I was trying to find the best songs sung by Vocaloid singers I started to find pieces of music that were suspiciously too good. By too good I mean, I wasn't able to tell for certain whether those were by a real person or rather by the software in question. My guess is that some people are starting to use the word Vocaloid to mean something else when sharing their work that might have nothing to do with the Vocaloid software.
Update: This post has a similar question "Is There a Vocaloid Anime?", though they are not clarifying if Vocaloids are only voice banks for the singing synthesizer software, or whether real people are starting to call themselves Vocaloids.