However, Satoshi did use an account on this forum, along with an email address. All connections to this forum logged his IP address/user-agent and other digital traces.
You can't do much with an IP address. It could be the IP address of a Tor exit node. Or perhaps another pro-anonymity protocol. Or VPN. Or maybe Satoshi just used to go on coffee-shops with free Wi-Fi to code or/and write forum posts. Or a combination of everything mentioned.
He probably just used Tor though. That's the safest approach.
By the way, Satoshi is not the only person in the cryptographic community who's remained anonymous. Monero's core development team is mostly consisted of anonymous people, like van Saberhagen and thankful_for_today. Today's anonymity protocols probably provide sufficient anonymity.
Internet Cafes were very popular in 2008. I remember that local internet cafes had no security cameras, were pretty expensive, the local government didn't have knowledgeable IT staff and I believe it would be super easy to be anonymous in 2008 than it is today.
It was just the right time and the right place for him to create a successful cryptocurrency and remain anonymous but it's really impressive that things stayed unknown for such a long period of time.
The general public still don’t have that information but somehow I believe the US government already knows everything about him. The thing is, sharing that info with us won’t benefit them (for now) so they are keeping it secret. The gov owns all the domains and the internet infrastructure. It is impossible to stay anonymous against the gov forever.
Maybe one day we will learn who Satoshi was but when that day comes, they’ll do that to achieve something else. Maybe create panic in the markets? Destroy bitcoin? Dump and pump? I don’t know, but something important will take place when it happens.
I think they don't know who Satoshi is or if they know they killed him or an unpopular opinion, the US agencies created Bitcoin.
I personally think that Satoshi wasn't wanted years ago, governments didn't really care about who created Bitcoin, and it only became mainstream and popular in 2016. Till 2016, satoshi had 8 years of unpopularity. No one keeps logs for 8 years, especially in 2008 when the internet was a new thing and the web wasn't as advanced as it is today, so I think that if we summarize all the services he used, most of his logs aren't kept and what's kept isn't enough to reveal his identity.
I think that Satoshi is the most self-disciplined guy. He didn't use his Bitcoins, never made a transaction and never took a single cent from the millions of dollars that his wallet keeps. He also never came back to the forum and he probably doesn't talk about Bitcoin in public and with his friends but to be fair, that's impossible too. Someone would have known his interest and expressions in cryptography and he shouldn't be able to hide it today when cryptocurrencies are mainstream. While I want him to be alive and to know who he is, my brain tells me that he is dead and that's why things are kept as secret till this day and forever.