There are facts and opinions that many people know which are super hard to find online:
If you go to a bar in a new city and strike up a conversation, you can find out a huge amount of information about neighborhoods, risk, feelings and attitudes of people in a city. Yet, if you want to find this out online, where would you go? There's no place I know. Reddit might be somewhat useful if the city is big enough and you search; crime statistics are useful (e.g. the charts on city-data) but I'd rather have a 20 minute conversation with a resident than any of those.