What does 888 mean in Japanese slang?

You'll see this on a number of forums and video streaming websites, and may even get it in a text from time to time. Similarly, you might see someone get praised with うぽつ (thank you for uploading) or 888 (pronounced as ぱちぱちぱち, the sound of snapping or clapping), which means “clap clap clap.”

Dunno how true this is since I don't speak the language, but I often see 888 in the comments on Japanese sides of Youtube and Nico Video.