This is great, thanks
@Xon for coming up with this.
I figured out that when you have XenPushover installed and your user account is subscribed to Pushover (both of these conditions in place) then your alerts are automatically "cleared" as you visit the threads for which the alerts are generated - regardless of how you actually visit those threads For instance, if you go straight to the site, and you click "new posts", etc, then read a thread that had generated an alert for you, that individual alert gets cleared and your alert counter bubble decrements by one. If you have multiple alerts and some of these are "likes" for instance, and you hover over Alerts, the drop down will actually momentarily show all alerts, including the recent ones that were just cleared (unbolded) as well as the "likes" that are bolded.
I thought this was due to an addon installed at TAZ (when using pushover) but then I saw it happening on one of my own sites, and not on the other...one with Pushover, one without. That's when I made the connection.
By default, XF does not clear any alerts until you hover over them (exception: ACP setting for length of time to retain alerts, but this is usually a long time). So if you get 50 email alerts, 20 likes, etc in one day, you'll have 70 alerts. You could have click the link on every email and viewed every thread, but all of your alerts would remain if you had never hovered over the alert tab. I've let this go for days and the alert bubble would reach into the 100's. This has always been a pet peeve of mine, one of the very few with XF but probably the one I found most annoying. Reason? If you view all the threads you were alerted to, but they don't all clear off the list, then you have a bunch of other non-thread related alerts that are all muddled in with thread alerts.
Within about 7 hours,
@Xon came up with this addon. And to paraphrase him - I can't believe that no one came up with this before.
So what happens now is that if you read all the threads that you got pushes (by any means, TT or Pushover) or by clicking the email links, those clear and all you are left with is...everything else. That tells you that you have more alerts than just threads, and alerts you would not get e-mails for (like alerts sent via ACP using new 1.5 features). But mainly, your alerts don't blow up to huge numbers.
Great addon, thanks again
@Xon