I'm about to enter into a relationship with a mentor in the coming weeks. I'm currently spending some time looking for the right person. I'm doing this through my contacts. Not just asking if anybody knows somebody who will mentor me, but actively looking at the right industry, and the right person.
I see a few problems with doing this on the web, and with doing this as a business.
1) I want somebody vetted who I can trust. I think in many ways this goes in line with VCs who say they want personal introductions. I don't want somebody who was randomly on the internet looking to mentor a start-up.
1) I know of a few wantrapreneurs who are 'advising/mentoring' start-ups, and I fear what the start-up is gaining from this experience. These people were presented to the start-ups/recommended as they had signed-up to be mentors through a network. I consider it a bit like some 'angel groups' that bring together start-ups to pitch, but never make any investments. These people are playing at start-up, and not serious enough to be worth a start-ups time (unless the start-up is just playing too, which also happens, I did it in the early days before I realized I wasn't being serious).
3) a fee per 15 minutes! Is this how mentoring works? I've never been mentored, but I hope not! This isn't an opportunity to nickel and dime a start-up. If a mentor is serious, they're probably wanting a piece of the action.
4) WebRTC has it's limitations (I used to work in the space) - it's great for a chat, you can share docs and annotate, etc with tools like Coviu (which I used to work on), but is there a reason to have a remote mentor?
Ok, that's a small list of reasons I wouldn't want to use a product you are describing, mostly due to my lack of trust in such a system.
On to this as a business for you.
1) How many people would need a remote mentor? Not everybody can be in the valley, but not everybody needs to be. There are successful mentors everywhere. It is doubtful that your start-up is in such a small remote location that nobody within a 100km radius could act as a mentor. I say this as a developer from a small town of 10,000 people. I've now moved to a much larger city, but even back in my home town, I could have found mentors with both knowledge and connections.
So, I'm going to say you are looking at a small market.
2) Money - as stated above. You want people to pay a small fee to discuss issues for 15 minutes - I think this is a bad business model. If I can't figure out how to get a meeting with an industry expert for advice, maybe I'm not in the right business. How can I expect to make sales in this industry if I can't get to the right people. So again, non-starter for me.
3) How do we navigate the pitfalls? We read and read and read. There is so much information online about generally getting yourself up and running that I'm not sure this is a general issue. Individual industries/verticals may have their own issues, but again, you need to be out there speaking to industry experts to figure this out.
BTW: have you looked into this already and come across https://www.geteverwise.com/ - I know there are other platforms out there as well, I remember seeing another that was not nearly as successful.