I also rarely get any spam messages anymore on my work email. But there are certainly many companies or departments within companies that have a culture of cc'ing anyone remotely connected to you. It's almost like a competitive sport--the more names on the cc line, the more important you must be!

But you're right, ILBob, the ease of sending email to multiple people encourages this phenomenon. Perhaps forcing people to communicate via, say, chat will enforce a new kind of discipline. Fewer messages to bother unrelated people, more brevity, and people forced to jot down only the most important info in a notebook (I already do this with emails).