It is, so is IE7.
Mainstream
Mainstream is, generally, the common current of thought. It is a term most often applied in the arts (i.e., music, literature, and performance). This includes: * something that is not out of the ordinary or unusual;* something that is familiar to the masses;* something that belongs to an identifiable genre, such as detective fiction, horror, fantasy, or science fiction.
en.wikipedia.org/wiki/Mainstream
Don't get how that means "Public". Mainstream is the majority of the public. The majority of the public use IE.