I regularly have recruiters coming to me with jobs in the Bay Area. I tell them that my salary requirement is double for up there versus Los Angeles. A few of the big players will always be able to afford that, but I see smaller tech companies and startups moving away due to cost.
I've seen plenty of "coders" with 15+ years experience maintaining and changing other peoples code that couldn't write code from scratch to save their lives. You see it mostly from people who've spent a lot of time someplace huge and old and corporate.
I applied for an analytics position that unexpectedly had me take a Python coding test like this (I know a bit of PHP and Java but no Python) and I was able to google everything I needed to pass the test in the time limit. Apparently I got one of the higher scores too. Got the job. It has not required me to write a single line of Python, lol.
I see no way of controlling privacy in a decentralized system. It'd be like trying to delete all the emails you've sent to other people or stop someone from forwarding an email. Once you put the data out there in a decentralized system, it's out there permanently. Centralization allows for some control.
That's easy. The ad network that serves you ads on YouTube also serves ads on Facebook. They have a profile of you that connects your facebook and google accounts.
Not just online activity. Bank/credit card transactions. Utility/tax information. Postal information. Subscriptions to anything. DMV records. A detailed profile of you is for sale to anyone who cares to pay. Probably less detailed than most people, since you're careful, but enough to be spooky.
They buy the info from massive data brokers, who buy data from other large and small data brokers, who buy the data from app makers, services, etc. [email protected] expressed interest in buying kitty litter isn't exactly sensitive information so there's probably not much in the way of auditable logs maintained, probably impossible to determine the original provenance of the data in many cases.
IP address, or if you have any shared accounts you could have a cookie identifying you as the same user. Ads also target connections of people who're interested in a product so you could get the ad from being friends/following someone who watched the videos. The ads will find you.
In Tucson AZ it was a constant problem that freight trains would either blow through town at full speed or crawl through level crossings blocking traffic rather than obeying speed laws. It was always cheaper for them to pay the fines than to comply.