As many members of this community know, I was previously employed for YEARS as a welder / mechanic while pursuing computer science as a mere hobby with the occasional freelance job. Three weeks ago I officially changed my full time profession to web development (as much as I dislike it compared to lower level topics).
In the past 9 years I have NEVER received any emails from companies or freelancing service providers that I didn't know personally requesting my services. In the past 2 weeks I've received 3...so what gives? Am I being spied upon? By whom? Google initially comes to mind as my work email (gmail) is 99% identical to my personal email address. I always joked about Google knowing more about someone than the person does, but now I have to wonder...has anyone else experienced anything like this?
Whenever you put a piece of information online, you should expect that it will never be deleted. Facebook doesn't delete a thing (even though they claim they do, and even their "anonymized" data can be easily reconstructed -- which is why they keep it --), and niether does google. Many sites sell info they collect to other companies, who partner with other websites like google. These companies compile metadata and can gather quite a bit of info on a person. For instance, google (the company) has information they can use to tell you what devices you use (and probably even for what, when you use them).
Information is also huge in the advertisement industry. These leeches will pilfer any information, however abiguous or irrelevant, in attempts to more accurately create targeted ads that NOBODY WANTS (seriously, why would I buy a product from a company that essentially endorses spying???).
If you have a facebook, twitter, or any other "social media" accounts, chances are they know enough about you to have a swat team raid your home. It's why I don't use any of that crap.
I'd hedge my bet that you probably communicate through gmail to set up your freelance contracts, and that you probably emailed back and forth when communicating with recruiters or even the HR agent that contacted you for your job. Gmail specifically collects your info to target ads at you through your email account (among other things). Google is infamous for its privacy policy, which provides no privacy at all.
You should also expect that somewhere, there is a file on you, automatically generated, that contains a sophisticated and highly in depth analysis of your personality, your habits, and your personal life. And this information is being updated constantly, your most likely next move, or purchase, constantly predicted. This, by both the government and hundreds of private companies, by algorithms.
They even sell smart TV's now that watch you back and send logs about what advertisements you're paying attention to. I know it sounds Orwellian, but this is Earth 2015.