TripAdvisor have recently changed their site to a secure one (using https) ie https://www.tripadvisor.co.nz/
This primarily affects your ability to track how much traffic you are receiving from TripAdvisor (and other https-secured sites). The result is that Google Analytics cannot collect data on referral traffic from these sites.
You will still be receiving referred visits (traffic), but these won’t be recording in your Analytics stats. That info is well worth knowing especially if you have a paid listing with them.
It you want Analytics to report this accurately, you need to either have a https-secured site yourself (unlikely), or set up some custom tracking urls in Analytics. These custom urls then need to be added to your TripAdvisor listing. Once that is done, Analytics will be able to report the visits.
The process is a little bit complex but full instructions for this are at
You may need to do the same for any other referring sites that are important to you.
Ask us to assist with this if you get stuck!