The Wikipedia article explains what it was, but not really its "place" or role or why it was valued?

I upvoted because I think the replies to this thread will be valuable.

https://en.wikipedia.org/wiki/FiveThirtyEight

Not from the USA, but I used the site to keep an eye on US politics.

538, named for the combined number of senators, representatives, and electors in the US, was a political journalism site. It used polls and data to ground its articles and opinions. Largely helmed by Nate Silver for a large portion of its run, until he left.

It got 49/50 states correct in the 2008 presidential election which catapulted it to fame. It never scored that accurately again but it's data driven charts and tables were a great pulse point for US politics. You could see recent aggregated polling data day by day in the run up to an election. And you could read analyses of polling data and trends.

There's nothing like it anymore, it didn't make money and didn't make spot on predictions reliably. It didn't need to do either, it was a good pool of data at the end of the day.

Everyone seems to rely on Polymarket now, which is a much more cynical way to aggregate polling data - by betting on predictions.