What you've done there is called taking a comment out of context. The next sentence is:
Most importantly though, I was not sure how big of an opportunity it was
The market for SAT preparation is limited to students sitting for SAT in a given year in the US. The market for Dropbox is everyone with a computer and internet. Yes, the online storage market is super-competitive, but when it's that big it increases the likelyhood that chasing it is worthwhile.
"What you've done there is called taking a comment out of context."
It's not out of context at all. I'm not misleading anyone with my comment, or putting words into the OP's mouth. My comment fairly represents what the OP said about the competitiveness of the SAT prep market.
My intent was to indicate that the online storage market is also highly competitive. It wasn't to present a point by point analysis of the full post.
The competitiveness of a company within a market, however, is highly dependent upon a value of the market segment they want to participate. This is what the second sentence means.
Differentiating and all of that don't matter a whit if there's no business to be had, but yes, you're right, it's hard to compete in a crowded marketplace. The thrust of the quote was more specific than that, though.
Most importantly though, I was not sure how big of an opportunity it was
The market for SAT preparation is limited to students sitting for SAT in a given year in the US. The market for Dropbox is everyone with a computer and internet. Yes, the online storage market is super-competitive, but when it's that big it increases the likelyhood that chasing it is worthwhile.