We have been using Subscribe to Comments for years. Then the plugin became obsolete and we had to switch to Subscribe to Comments Reloaded (StCR). It's a nice plugin, but we often found that we had to put in our own fixes to be able to use it for our clients. Let's sum it up:
- doesn't modify core WordPress database tables
- import's Subscribe to Comments data (although I'm pretty sure we had to do it by hand in earlier versions)
- subscription manager page gets the same design as your website, unlike the Subscribe to Comments plugin
- unsubscribing was slow and hard - that's why we created Subscribe to Comments Reloaded Better Unsubscribe - single click to unsubscribe
- people reporting that they receive multiple "Manage your subscriptions" emails - Invalid "Manage your subscriptions" link triggering more and more notifications
...and more recently - Google PII warnings. Suddenly our clients were complaining that Google doesn't like their website because it's breaking the AdSense privacy rules and that their AdSense program will end in 2 weeks.
What is the Personally Identifiable Information
Website ad units store a lot of cookies to track the websites which the user is visiting to only show the relevant ads. Problem occurs if you have a website which manages user accounts and if you show the person's name or email in the URL. Which is exactly the case of StCR, as the unsubscription URL looks like this:
As you can see, the user email address is right there (url encoded).
All it takes is to load an Google AdSense ad unit on a page like this and the ad network knows the browsing history (if the sites include Google AdSense ads) of that email address.
StCR is getting fixed, but it's taking a while, see Google claims personally identifiable information is being passed on · Issue #79 · stcr/subscribe-to-comments-reloaded on GitHub.
What's why we put another improvement into our Subscribe to Comments Reloaded Better Unsubscribe plugin: we simply force a bare-bones template to be loaded for subscription manager. That means there can be no ad units, since we don't load your header, footer nor sidebar.
This is a great fix and now we don't have to wait for another client to come to us asking us for help with Google threatening to shut down the ads for his website. Hopefully StCR will get a proper fix and then we can disable this feature or make it optional.