The red bell is for notifications of thumbs and acorns, not responses to questions on threads. We all have the option of personalizing our home pages, so yours might look different, but there should be a listing of "Watched Threads" on your home page. I've got mine at the top above "Recent Threads". If you start a thread, it should show in that list whenever someone replies ... but I'm pretty sure you have to set that in your profile settings.
