This is a continuation of a series about the three main types of alerting systems; subscription, opt-in, and mass/intrusive.
Pros and cons of subscription based alerting systems
A subscription-based system is defined, loosely, as one where a subscriber has to voluntarily both consent to using the service.
When you think about alerting systems, you should always keep in mind that they are essentially just like any other communication method used to reach a large number of individuals. You’ve got something to say to your audience, maybe it's advertising your new product, and you need a way to reach them. With this thinking in mind, a (very) simplified breakdown of the types of alerting systems yields three main categories: subscription, opt-in, and intrusive.
A subscription-based system is defined, loosely, as one where a subscriber has to voluntarily both consent to using the service and provide personal contact information. It's a high burden of entry. A list of these subscribers needs to be created and maintained by that system. An example of this type of system might be your Christmas card list (postal addresses), a monthly newsletter that you produce (email or postal addresses), or an emergency contact list for your child’s classroom or sports team (phone numbers). In each case, you need to establish a relationship with the potential subscriber, demonstrate to them the value of joining your list, deliver on that value to keep them engaged, and of course keep their contact information up to date as time goes on (new phone/address/email, job changes, life changes, etc).
A positive benefit of maintaining this subscription-based system is you establish a personal relationship with your subscribers. From a marketing/advertising perspective, you’ve now clearly identified your target market and captured their attention. This relationship needs regular maintenance, but when it's in place, it ensures that your message is well received and acted upon, such as during an emergency. However, the larger your list becomes, the more difficult it is to maintain these relationships. In some cases you may be asking the subscriber to surrender a lot of personal information to join, privacy can be a valuable commodity, and if they don’t already have a high level of trust in your organization, the risks can outweigh the rewards. Another negative outcome of having a large contact list is not just low mass market penetration, but maintaining that list becomes more and more of a burden. At some point, that burden may even outweigh the benefits to you the maintainer, especially for a list that is rarely, or even never, used.