Yes, there are dozens of these data enrichment companies. They scrape public sites and use browser extensions, SaaS tools, inbox addons, etc. They mix it together into profiles, and pretty much have the same dataset by now.
Yep! And as someone who has worked with these data sets and worked on the scraping tools on services like LinkedIn, a lot of the data is outdated, incorrect, or mixing together different entities with the same name into one person or splitting the same person into separate entities incorrectly.
Clearbit is one of them and even a YC company.