@Will ScarletOk, another issue. Being able to select if you want to receive e-mail updates to a thread used to be under the Post Reply, now it seems to be automatic. You should be able to select what kind of notification you want when posting and not having to dig through your profile to change it.
You can update those default settings here then should be able to update them under following:
A red dot on your avatar near the upper right-hand corner of the site, indicates that you have alerts or new conversations (private messages). When you click on your avatar you will see a number next to Alerts and/or Conversations indicating how many new ones you have. Click on each to view them.
You can adjust your settings for alerts by selecting Account Settings and then Preferences from the left side navigation on the new page.
Scroll down to “Receive a notification when someone…” and set your preferences.
For email alerts, scroll down to Content options and adjust your settings.
Make sure to click Save at the bottom if you make any changes.