Patrick and I were discussing a regular problem that I have - I get more people coming to me (or ocProducts) directly to make requests and report bugs, than using the tracker. For example, I get Twitter DMs, I get private topics, I get emails, I get Skype messages (until I have to block someone for regularly interrupting my workflow), and so on. It's not sustainable for me to be the locus of all activity, but at the same time I don't want to lose important engagement by pushing people away or ignoring people.

We decided this behaviour is probably for one of the following reasons...
1) People can be shy about posting in public
2) People have actual confidential information that is a part of a discussion (and don't want to take the time to separate that out)
3) A lot of people prefer to engage with individuals than systems, as they prefer or are used to, the personal touch
4) ... or they specifically find particular systems intimidating (hence #4999)
5) It's simply quick and easy to talk to someone you already have a relationship with directly
6) People don't know the correct process and don't want to take the time to read the guidance (and the guidance is necessarily either too brief to be accurate and helpful or too long to read)

Patrick's solution (which I like) is this issue - incentivising people to use the tracker. Plus I can directly tell people, "if you post on the tracker you'll get lots of points for it" as a simple way to quickly reply to people.