If I'm at a bar and want to settle something lighthearted between friends, Wikipedia is the source of choice. If it's worth delving deeper, we'll go deeper, but for a quick answer I trust Wikipedia more than saying "Hey Google, which network was the first iPhone exclusive to?"

Perhaps irrefutable is too strong a word, but if I'm looking for an answer (instead of researching a topic) and want a quick, single source, Wikipedia is my go-to.