You can add query string variables to the survey link and then capture that information within hidden value fields in the survey (We are hoping to pull together a full blown tutorial on using query string variables soon).
For example, here is a made up basic survey link:
http://www.surveygizmo.com/s/12345/my-survey
You could have your website build the link and add a variable named 'name':
http://www.surveygizmo.com/s/12345/my-survey?name=Bob
These are automatically captured by the survey, but to be able to use the value within the survey for skip logic, it would be best to save it in a hidden value field (ADD ACTION > HIDDEN VALUE).
The 'value' of the hidden value field would be the merge code: [%%GET_name]
All query string merge codes take the form of [%%GET_xxx] where xxx represents the variable name. This stores the value of 'Bob' because that was what name= was in the query string. You would have one hidden value field for each variable in the query string, such as name and type … ?name=Bob&type=survey