After doing some more research, I realized that I already had quote notifications on my site, just didn't have them turned on. They were under the 'Who Quoted Me' modification options and I found a subscribed threads notifications on vb.org as well but the problem with that mod is that the notifications won't go away unless you click on all of the subscriptions. I prefer this vbnotifications modification because once you x out the box it goes away and a member can have the option of turning of subscribed threads.