I really hope you don't mind me asking such a trivial question but I tried using the search bar and couldn't find anything that actually worked.
Within my profile, I have my first quest to complete which contains 5 objectives. 3 of these are done, the other two are "Mark a document as helpful" and "Mark a comment as helpful". Now apparently the helpful button is no longer available and the like button supposedly does the same thing. If this is truly the case then this quest should have been completed before I even realised I had it lol.
Just to test the theory, I searched for a document on weldments (which is something else I will need to brush up on shortly) and clicked the like button on it. It hasn't changed the quest outcome though. Any advice?