I apologize for the confusion about managing your email alerts on Trulia. As you've already surmised, the alerts stem from the properties that you are currently following. If you access the link below to navigate to the "My Homes" section of your profile, you'll see an option to "Manage alerts" for each property you have saved. Once you click on this link you can specify that you'd only like to receive alerts when the property price or status changes, and that you don't want to be alerted about similar properties.
Let us know if you experience any difficulties making these updates or if you have any other questions.