What does the sharp and exclamation mark (#!) stand for in a url? Don't even know how to look for an answer

Question

I have seen these "domain.com/#!/" formated urls, and driven merely by curiosity I chose to ask you people... what is that used for? A kinda "exclamated-hashtag" if you know what I mean. I see it on sites such as "hypem.com" or "buzzchips.com", both of them delivering asynchronous dynamic content in a similar way.

I uploaded a tiny shot just so you actually see what I see, here and there.

Answer 1

You can see a good explanation of this under the SEO heading for the following answer: https://softwareengineering.stackexchange.com/questions/46716/what-should-a-developer-know-before-building-a-public-web-site/46760#46760

Answer 2

It appears to be a standard for allowing dynamically created content to be crawled.