The web changes, its a simple fact.  How users interact with websites changes as more sites adopt functionality.  Some basic principles will never change and should not be ignored.  However, remember that “cool” functionality you thought was cutting edge and you spent hours developing 3 years ago which you removed because of a drop in clicks, sales, etc…  Why not try it out again?  If it was unfamiliar to users, it may not be so now. Chances are by now, someone else is doing it and chances are they are seeing positve results.  So uncomment the code, review the change and try it again.