The short answer has to be anyone who wants to do business on the Internet.
I’ve been using a lovely little package for a while now called Stat Counter. You can use a free version that does everything the standard package does but limits the log files.
It’s proved to be so useful.
I looked at my site analysis and noticed that everyone was going to the contact section and leaving in droves. So I’ve changed it!
I’ll see if that improves the situation.