The website contains many users who are skilled and know what they are doing in the field. For example if a person had to do a engineering report, is the stack exchange able to be to cited?
From the Stackexchange Terms of Service page:
In the event that You post or otherwise use Subscriber Content outside of the Network or Services, with the exception of content entirely created by You, You agree that You will follow the attribution rules of the Creative Commons Attribution Share Alike license as follows:
You will ensure that any such use of Subscriber Content visually displays or otherwise indicates the source of the Subscriber Content as coming from the Stack Exchange Network. This requirement is satisfied with a discreet text blurb, or some other unobtrusive but clear visual indication.
You will ensure that any such Internet use of Subscriber Content includes a hyperlink directly to the original question on the source site on the Network (e.g., https://stackoverflow.com/questions/12345)
You will ensure that any such use of Subscriber Content visually display or otherwise clearly indicate the author names for every question and answer so used.
As for how you would cite it, you would use your Style Guide's rules for a single webpage. For example, MLA Works Cited, Electronic Sources (Web Publications):
Important Note on the Use of URLs in MLA
MLA no longer requires the use of URLs in MLA citations. Because Web addresses are not static (i.e., they change often) and because documents sometimes appear in multiple places on the Web (e.g., on multiple databases), MLA explains that most readers can find electronic sources via title or author searches in Internet Search Engines.
For instructors or editors who still wish to require the use of URLs, MLA suggests that the URL appear in angle brackets after the date of access. Break URLs only after slashes.
Aristotle. Poetics. Trans. S. H. Butcher. The Internet Classics Archive. Web Atomic and Massachusetts Institute of Technology, 13 Sept. 2007. Web. 4 Nov. 2008. ‹http://classics.mit.edu/›.