This is a good question. Because learning piano takes time, you will want to minimize the chance that the program you choose won’t disappear on you in a few weeks. I have seen it happen, so buyer beware!
ANYONE can sell a piano program online! That means you can too! What does that tell you?
Unfortunately, this can cause piano teaching products to go on the market and be low quality and may even be written by good musicians but not by experienced teachers. These types of products tend to come and go because the owner is either a reseller and not a teacher, or the teacher is a hobbyist and not a professional or full time teacher. Owning a business online as a reseller or hobbyist can be short lived due to lack of commitment to the customers.
To avoid purchasing a product that might not stay on the internet long enough to support you, don’t be afraid to ask how long your “piano teacher” has been online and how long they’ve been teaching online. It wouldn’t hurt to dig a little deeper to see if your online teacher offline as a career as well. This is a sign of commitment. Don’t be fooled by pretty pages and fancy promises! A little research can go a long way when shopping on the internet!