As WMF's research efforts expand (great!), we're seeing more and more surveys. Some of those are being linked from MediaWiki itself, see for instance Qualtrics at T1005 and previously SurveyMonkey for MediaViewer.
It can't be given for granted that sending users to third party websites from our interface is allowed by the [[https://wikimediafoundation.org/wiki/Privacy_policy|privacy policy]]. It would be nice to determine what service are fine to link and document the outcome, for instance at the master list of software used by WMF, https://meta.wikimedia.org/wiki/FLOSS-Exchange
Note that this matter is distinct from the questions 1) whether it's appropriate to use unfree software, 2) what software is statistically suitable, and 3) how multilingual they are/how good their i18n and integration with the [[https://www.mediawiki.org/wiki/Help:Extension:Translate|Translate extension]]. The discussion about that was at http://thread.gmane.org/gmane.org.wikimedia.analytics/345/
As for privacy:
- #WMF-Legal has vetted Qualtrics and it has gone through the Contracts team.
- LimeService seems rather good but should be verified. https://www.limeservice.com/en/pricing/21-english/general-content/39-data-protection-statement They don't need Safe Harbor because they already are in EU (with Canada option).
- SurveyMonkey has some privacy policy, as well as certifications and EU branches for EU users plus special articles for Canada, Japan, Australia and Brasil users. https://surveymonkey.com/mp/policy/privacy-policy/ (Didn't read yet. They also use Google Analytics and other third party stuff, while I don't remember whether/when Qualtrics does.)
- Google Docs is sometimes used for events feedback etc. and by the community because it's very easy to set up, sometimes widely advertised e.g. [[https://id.wikipedia.org/w/index.php?title=Templat:AdvancedSiteNotices&oldid=9529424|id.wikipedia sitenotice]]. Privacy doesn't exist, it's the general "do whatever you want" Google policy.
- Other?