about の用法 (3)

A: Nowadays, almost every TV and radio presenter looks like talking about this "hashtag" thing. What's it all about?
B: It's a symbol # combined with a key word, which is used to categorize tweets according to a certain topic or subject so that Twitter users can easily follow relevant info in the Twitter space. That's what it's all about.

この英文の日本語訳は近いうちに掲載します。お楽しみに。