So the challenge with tracking respondents comes in with mapping their response to a contact record. The simplest way to do this is to give each respondent their own unique URL to use when responding to a survey so the trouble of authenticating the respondent is not put on the end user. However if you have a URL that you want to re-use in an email signature, then you can't use this method.
This is why when creating a survey in Gainsight you need to specify if you want to allow anonymous responses, as this changes the way that our survey tool generates the survey URLs.
Another way (Gainsight doesn't currently offer this) that you could track the user is if you required them first to log into a portal or application and then present them with the survey "in-app". Since they already logged in, you have their identity already captured.
VP of Customer Success at Forcepoint