SE.DSP is peer reviewed to some extend. Not in the traditional "journal" sense, meanwhile predatory publishing or randomized peer-review, to name a few, have changed the deal. A post in SE.DSP can sometimes be much more peer-reviewed than a paper in some conferences/journals.
However, SE.DSP as a site has no DOI. It can vanish, questions and answers can be edited, deleted. There is no means, as far as I know, to freeze a citable version, as you could do for other web sources like wikipedia. Suppose that you cite a page for a "true result", to sustain a part of you paper. If it changes, turns wrong, or disappears, your results may remain correct, but without a source. In that sense, SE is not auditable at the time of writing. As said in Citing References in Scientific Research Papers:
It is important to properly and appropriately cite references in scientific research papers in order to acknowledge your sources and give credit where credit is due.
And about the sources:
Sources that need to be acknowledged are not limited to books and journal articles, but include internet sites, computer software, written and e-mail correspondence, even verbal conversations with other people (in person or by telephone). All different kinds of sources must be acknowledged.
So I doubt a Q&A link can be used directly, as of today, for a "scientific publication". But... a publication is about making something public. It does not anymore restrict the sole paper pdf. So I propose these options:
- if you want to pay credit to SE.DSP, vote answers up, share the OP, put a link to the related answer on a blog, webpage, etc. together with a link to your paper; you can even refer to the main SE.DSP site as a source of inspiration;
- if you want to pay credit to someone, ask him for the reference, thank him in the paper, add a "personal communication" to the reference list. But you likely are to rephrase the mentioned result in your paper, so that it can be checked. You can even collaborate with someone;
- if you want to pay back: add your answer, contribute the community wiki. Perhaps one day our community wiki will be truly citable;
- [EDIT] As proposed by Marcus Müller (credits well deserved), one could resort to forms of digital archive. This link to Citing from a Digital Archive like the Internet Archive: A Cheat Sheet proposes techniques to do that. There was also a quora question on How should I cite an archived version of a web page in APA style?