Sometimes you really are only as good as your technology. You absolutely want to get a look at what the learning management system (your “classroom”) looks like before signing up. You may be surprised to discover that much of their program is actually completed off-line and that the only online component is when you upload your work.
If that works for you, then all is well and good. For many students, though, the hope is that there is something more interactive in nature. There should be a way for a school to show you what this all looks like. If they cannot, you have every reason to wonder why that might be so difficult for them.
Beware of a lack of transparency. It is not a deal-killer, necessarily, but it does mean that you need to do more research.
So, what are you looking for? In essence, you might see audio components, video components, some way to interact with teachers (and, perhaps, students), and more. It should not be: “Here’s a textbook that we have thrown up online. Here are questions. Answer the questions.”