It basically refers to data in salesforce being complete, accurate and input in a consistent way. It's a term used around software apps that drive decision making and are useless without the criteria I mentioned.
It's funny how much people hate Salesforce. People used to say the same thing about ACT back in the day. I mean, SF is a total POS, but whatever.
I'm not sure why these sales tools have to be so crappy. I guess there's a market for good sales tools. The Marketing CRM tools (hubspot et al) are much nicer.