더라고요

I noticed — reporting your own experience

Reports something the speaker personally witnessed or discovered, with a flavour of it turned out that way. 맛있더라고요 "they turned out to be tasty", 정말 쉽지 않더라고요 "it really wasn't easy, I found", 연락 왔더라고요 "turns out he called". The key restriction is that it must be firsthand — you saw it, tasted it, felt it — so it is not used for things you merely heard about. That firsthand stamp is exactly what separates it from 대요 or 라고 해요, which pass along someone else's report. Drop the 요 for the casual 더라고.

Register: polite conversational; extremely common in vlogs