Supertracker

[a_berezin]

But I still have 0 recors for each report that involves Referrer.

You have no referrers.

What referrer actually means and how should I use these reports?

Referrer is very important information in internet marketing. Mine poor English does not allow me in detail to tell about importance of these reports. May be somebody else?
Referrer in wikipedia - http://en.wikipedia.org/wiki/HTTP_referrer