- Knowing terminology of the field is important for quick communication in the team. E.g. We're going to do cache invalidation with LRU is harder/imprecise/longer to communicate without those words even if you have implemented it in practice.
- Sounds like you spent 2 years full time building projects. You can't call them "side projects" that you did for fun/learning, they sound more like real attempt at making an indie business (good for you). It's a significant time investment. You need to be able to talk about your project intelligently. Know everything you have used to get there: build tools, web frameworks, database schema, OO design & how it all fits together. They won't ask "point" questions about your demo, they don't care. More important is what all you have learned from the projects and being able to articulate it is important.
- Finally, why swim against the river flow? If you are smart enough to build social media platforms by yourself (with no CS background), you can very easily pickup a few books and learn the fundamentals of Data structure, algorithms etc. It's not very hard to excel at white boarding (if that's what they want to see).