It's very easy for others to find out what you've been doing online. I know this makes a lot of people shrug and say, "but I'm not doing anything illegal, so who cares?" That's not a bad point, really. However, to those same folks I say, "How much do you like spam?"
Not the canned variety, of course, but the digital kind that fills up your inbox. Want a no document mortgage? You could flip those houses and grow rich, if you sign up for the super-secret e-course that hundreds of thousands just got an email about. And you'll probably want to get certain bits of yourself enlarged, because all of that money is going to get you a lot more action - never fear, you've got mail on that subject, too.
How many of you catch your "delete" key on fire each day from pressing it so much? Probably a lot.
One way to avoid the prying eyes of annoying marketers is to use a virtual private network, or vpn for short. A vpn is essentially a group of computers which grant exclusive access to each other, transmitting their encrypted data back and forth over a larger, third party network (the Internet). This allows an organization to enjoy the functionality of a private network without having to invest in actual physical connections between parties, allowing effortless scalability and reach.
In terms of internet privacy and general use, a vpn can act as an anonymous intermediary between your computer and the wider web. Your data (search requests, URLs, etc.) travel a secure, encrypted "pipeline" between you and the vpn's servers, which go out and fetch your data, then return it to you over your secure connection to the server. The site on the other end only sees the vpn server arrive, not you. This isn't a total fix for securing your identity from those annoying marketers, but it helps (I like to turn off third party cookies, too - this eliminates a lot of crap that is tucked away in banner ads and whatnot).