Who marinates?

[Chefnot]

Cooking 101: Reasons to marinate your meats
Independent and Free Press, Canada - 7 hours ago
I say protein, because not only do we marinate beef, pork, lamb and chicken, but also fish. A marinade has three main ingredients: an acid, ...

[Food Network Fan]

Depends on what I am making. I do sometimes.

[BerryBaby]

Only when I'm making Carne Asada.

[ibcheft]

I was told or thought that if you put salt in with the marinade it would cook the meat, that is why you do not, did not know that it also toughened the meat, and yes I do, like FNF, depends on what I am making

[Clove]

Originally Posted by ibcheft

I was told or thought that if you put salt in with the marinade it would cook the meat, that is why you do not, did not know that it also toughened the meat,...

When you think about the technique that is used for marinating and then compare it with brining, you'll see the fallacy in the statement of "toughening meat".
If that were true, brining a turkey for 24 hours in a salt water bath, would give you a very tough turkey. In fact it gives you a tender and juicy bird. That's why so many commercial producers add a 1 1/2 to 2% salt water infusion to their birds.
The same can be said for brining pork too.
The acid in a marinade can "cook" (or break down) the protein in a seviche way. That can happen but the salt issue is very suspect.

[Chefnot]

We marinate quite a bit and use different brines as well. I have never attributed toughness to either, I don't think I have ever heard that.