Hi,
All the popular ones will 'track' you, but some are far more intrusive.
The very worst I ever came across (and I mean I was shocked and I'm not easy to shock) was Google's Gmail "Web History".
It's like something straight out of the movie 'Enemy of the State'.
I don't know if you've seen it but the government is tracking (in the extreme) Will Smith and they
know every time he so much as blinks, using with all kinds of satellite tracking systems, implanted tracking devices and all kinds of 'space-age' methods.
If you use Gmail, login and look at your 'Web History'.
It will show every single search term you've ever searched on Google, as well as a list of actual sites you've been to.
I know this sounds like some kind of nut job conspiracy theory, but just look for yourself.
In fact they even spell it out.
"Account Activity:
With Account Activity you can learn what's going on in your account, e.g. how many emails you have sent and received, how often you have searched on Google, from which countries you have logged in...
Every month the Account Activity Report will collect and summarize data across your Google account – e.g. sent emails or top searches.
Data deletion at the data source, e.g. in your Web History will have no impact on issued reports, however reports can be deleted at any time."
Note the:
1) "...how often you've searched on Google..."
2) "...collect and summarize..sent mails or top searches."
3) "Data deletion...will have no impact..."
To see your Gmail Web History:
Login > click 'Gear' icon then Settings > under Change Account Settings: area, select 'Other Google Account Settings > click Dashboard > scroll down to Web History
If it's enabled, you'll see quite a surprise.
Every, single last search term you've ever searched on Google.
A couple of helpful things to know:
1) "Stay signed in" - NEVER leave a check mark in this box.
2) Turn off Gmail's Web history: Sign in, then: https://history.google.com/history/?hl=en&ctz=300
3) Tracking Protection Lists (TPLs) in browsers. These will tell web sites, explicitly, "Do not using tracking cookies with me".
However, (now check this out), at one point last year Google issued a statement that they would not honor a Tracking Protection List's request not to track!!
You can Google (how ironic) for news articles about the fight between Microsoft and Google regarding Tracking Protection Lists.
Ok, with Internet Explorer 9 (and I'm sure 10 is the same):
Go to Tools > Tracking Protection and make sure at least one is 'Enabled'.
If none are listed, click "Get a Tracking Protection List (TPL) online...."
"Abine Standard" at the top is a good one.
Next, use 'InPrivate Browsing' (Tools > InPrivate Browsing)
For Firefox, this simply means checking the box in Settings that says, "Tell websites I do not want to be tracked."
So, there's a few tips on a couple of ways to stop getting tracked all over the place.
If my answer helps you, please vote me Best Answer.
For further clarification of my answer, if needed, contact me directly.
At your service,
Hugh
.