I see a lot of ads that list a top speed and cruising speed for their boats...What actually is a "cruising speed"???

If my boat does 65 m.p.h. at WOT that is my "cruising speed" 9 out of 10 times.

The flip side of that is if I'm cruising for chicks my "cruise speed" is 5 m.p.h.

SO WTF is a cruise speed?