Update Details Below. Note that if the dialog shows an older version you may need to recreate your bookmarklet.
Also note that this will probably only work in English, though you may be able to temporally change your language on Netflix to get the sync to work.
There used to be a nice Chrome plugin to synchronize by Netflix history with Trakt.tv but it had been unreliable and doesn't seam to be working now. I wrote this code to solve my own need but it does the same thing and I am posting it here for others to use.
Note that this is not 100% perfect as some show names aren't exactly the same and some Netflix show's don't use episode names at all. This code it not using any Netflix API calls but rather just scraping your Viewing Activity page and then making API calls to your Trakt.tv account to post the item's it finds.
Project Licenses
These works by Jeremy Pyne are licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License