The big problem with this is you're giving the site access to loads of information about you. That's scary because the sites that use your credentials from Google, Facebook, LinkedIn, Twitter and other sites suddenly have access to your name, photos, email address and more information that you'd like to keep private.
We're all guilty of letting our guard down when it comes to privacy. It's understandable - who wants to type in pages of information about you to sign up for a new site when you can just let the site grab that information from Facebook?
Worse, you've probably signed up for dozens of sites this way over the years. The good news is, it's pretty easy to find out which sites are spying on you by checking your profile on Facebook, Google and other social media sites.
To find out which apps can access information about you on Facebook, you start with the menu. That's the down arrow to the right of your name on your Facebook news feed or timeline. (See red arrow below.)
Click on Settings >> click on Apps on the left-hand side of the page >> then click on specific apps to see what information they can see, like your email address and birthday. This is creepy. You might also see a note saying the app can post messages to Facebook on your behalf. This is what it says.
If you want to change the information that each app can use, click or un-click on the blue circle with a white check mark in it. When you don't want an app having access to your friends or email address, for instance, click on it.
The blue circle will be grayed-out when you turn it off. It's a bright blue when it's on.
It's incredible how much information we are letting apps access, isn't it? Of course, these aren't just apps.
They are companies with people who you're giving permission to spy on you. Worse, you're sometimes giving them access to all your contacts - friends, family and coworkers.
In some cases, you're letting these apps who you don't know post messages online for you. You've given them permission to do that, but you've got the power to block what they share.
On Google, you start by signing into your account. You can log in from Gmail, Google+ and other Google sites.
Click on Settings (see red arrows below) >> under Sign-In & Security click on Connected Apps & Sites >> Manage Apps. Click on each app to see what information they can access and manage that accessibility. You can also click on Remove Access.
LinkedIn is a great site for connecting with coworkers, potential clients and future employers. The career-focused social network has hundreds of millions of users.
You should be careful using LinkedIn, though. The site is notorious for its fake profiles, where scammers use someone else's photo and personal details to trick you into sharing your information with them.
LinkedIn also isn't great about giving you control over the access that apps have about you. However, you can entirely remove apps that do track you.
Here's how to remove apps that track you: Click on the down arrow next to Me and below your photo, near the center of the top of your home page. Select Settings & Privacy >> Partners and Services >> Permitted Services >> choose Remove to the right of apps you don't want tracking you.
You can revoke access to apps on Twitter. Start by clicking on your account and selecting Settings and Privacy >> Apps >> choose Revoke Access to the right of apps you don't want tracking you.
Speaking of apps that spy on you, here's a creepy list of things social media sites know about you
The next time you're asked to share personal information with social media platforms, think twice! Users of this particular platform are learning that the hard way. They thought they were only agreeing to share a few details, but it's alarming what was buried in the fine print. Are you being tracked around the web by social media sites?