First of all a ham hock is a portion of a pig's leg (go look it up). It's mostly fat and bone and about one third meat but the meat is not the most important thing you're looking for; it's the flavor. The meat is just an added benefit. The smoked hock has a smoked flavor, you get flavor from the fat and flavor from the bones. It's called "body" in the flavor world.
Now,
smoked hocks come in two forms, One is as big as shown in the first
picture and the other is cut in crosswise slices with a bone saw; it's
all the same. The sliced type needs to be cooked just as long because
it's not about getting the meat done, it's about extracting flavor. I
score the fat layer in a few places on the piece shown here before it's
put to boil. 
To
handle the hock properly you must slow boil it for at least an hour, and,
more time is better. Boil it until it falls apart; don't worry, the meat
is tough enough to handle it. Take the hock of out the water and reduce
the liquid by half. The picture here is of the hock after it's taken out
of the pot to cool. 
The
third picture gives you an idea how much meat you'll get out of a large
hock. It's in a small paper plate and amounts to about a little over a
cup. You'll have to pick and pull the meat out of it and discard the
rest. You will also notice that very little dissolved fat is in the
water! So, you're talking about a one to two hour process altogether just to get everything you want out of the hock flavor wise.
What would you do with a smoked ham hock you say? Pretty much what you would use salt meat for, however, it has a smoked flavor (body) that salt meat does not have. Purple Hull Peas love Smoked Ham Hocks.