I was answering "when" to deduct start-up expenses. How to deduct them is a whole other article. Some expenses can be deducted as expenses, some must be amortized, and assets must be depreciated.
"I read that the question is not when you create your LLC but when you act like a business. Is building a website enough to act like a business? Is adding information to my website (videos, tutorials, blog posts, etc.) to attract people (marketing) enough to deduct those expenses?"
You must be actively engaged in the business. What exactly that means depends on the business. If you are posting content online with the intention that people will see it and interact with your business, that sounds active to me. If you are creating a content library but have not started to post/share/distribute it, that's a tougher question, and if you don't have a clear sense of whether you are "actively" engaged in business, you might want professional advice.
