I've moved your thread to the Tech Support & Site Help Forum so that other members could be made aware of your question, and this answer. In a word, Yes, you can set up your subscriptions to suit your preferences.
Click on User CP, and in the page that opens, you will see a list of the threads you're subscribed to. You can, of course, turn this feature off completely, but since you want to receive email notifications when the threads you're subscribed to update, that won't work for you. What you want to do is turn off your subscriptions to other threads you don't
care to be notified of updates.
Under the title of the threads on your subscribed list, you will see the option to Reply / Unsubscribe. By selecting Unsubscribe, you will no longer receive the email notifications for the threads you have no desire to be notified of when they update. Just select Unsubscribe for each thread you don't want, and leave the ones alone you do want, and you will only receive the notifications for your chosen threads.
If, like me, you're subscribed to 2347 threads, you probably don't want to go through all of them and Unsubscribe from all but the few you want to stay Subscribed to. In that case, click on View All Subscribed Threads. In the page that opens, you will see that you have the following options: View All Subscribed Threads / Edit Folder / Empty Current
Folder. You can select Empty Current
Folder, then select Yes when asked if you really want to do that.
Once the Subscription Folder is empty, keep it cleaned out of all but the threads you wish to receive email notification of updates.
PS: Or just ignore everything I typed, and go with Hud's much better, more succinct, advice.