Is word "crap" considered a vulgarism?

I wouldn't label crap as vulgar by today's standards, but it isn't a word you'd want to use in a professional setting or with people who are prim and proper.

The word itself is used in a many different ways. kiamlaluno pointed out two popular usages:

• Something that is of extremely poor quality: nonsense; rubbish, junk.
• excrement: (in singular) an act of defecation.

But it is also used as an exclamation, as in:

Holy crap, this test is difficult!

I do think that the word crap has become more acceptable over time. When I was a child in the 80s I once said, in front of a friend's mother, "This is crap," after seeing a long line at an amusement park. She gave me a very stern look and told me I should not use such vulgar language.

Another time I was helping a classmate clean out his desk and I said something along the lines of, "There is a lot of crap in here," and he shushed me as he was concerned that we would get in trouble if the teacher heard us using that word.

Well, it's less vulgar than its synonym "shit", and more vulgar than the term "junk" or "garbage", so it's a matter of scale. I wouldn't use "crap" in polite company, or when speaking to a customer.

Coincidentally, when broadcasting on TV or the Radio in the USA, it's OK to use the word "crap", but illegal to use the word "shit", so it doesn't need to be censored.

The meaning of crap is

• Something that is of extremely poor quality: nonsense; rubbish, junk.
• excrement: (in singular) an act of defecation.

The first meaning is similar to the use of the work cock in the following British English sentence:

That's all a lot of cock.

The NOAD doesn't mark the second meaning of crap as vulgar, and I don't think it is interpreted as vulgar from people too.
To make a comparison, also the word cock is not considered vulgar, as it has other meanings apart penis.

If you are, or want to be perceived as, a mature, grown-up person, you will not use the word "crap". It is understood to be another word for fecal matter. Why would you want to talk about what you do in the bathroom? Yuck. I sure don't want to hear about it in polite convo. That's just gross. Keep it to yourself.