What is Asymptomatic Shedding

What is shedding and when does it happens? Do we know it is happening? How many people asymptomatically shed? I see this phrase mentioned all the time.

Asyptomatic shedding is when the virus is being shed
from the body without showing any visible signs of an outbreak.
Unfortunately we can't tell when this is happening, or it would
be a lot easier to keep from spreading the virus to others. It is
said that the body sheds less often the longer you have the virus
in your system, in the first couple of years, you'll shed more
often then years down the line. It can be reduced significantly
by using daily anti-virals, but it won't stop it completely.
How much the virus is shed is also dependant on what form of the
virus you have, and where you have it. I, for instance have HSV-1
genitally (the one that normally is present orally). Since the
genitals aren't its major site of preference, it sheds the virus
less often then it would if it were on my mouth. HSV-2 genitally
will likely shed more often, as it would be at its site of
preference, while it wouldn't shed as often if it were found on
the mouth.

I recommend taking the time to read the online herpes handbook
It is some of the best information on herpes I've read. There is also a section on how to reduce the chances of transmitting it to a partner and what precautions to take.