One way to keep track of those is to leave them in an open tab in your browser till you get to them one day (a method I've been famous for using).
That usually isn't a good solution because when you do have the time to check out a video or a few minutes to read an article, you may not be next to your computer, you may be away from home with your iPhone or just lounging around with your iPad.
Instapaper is the place to save all that content and then consume it when it's convenient for you. The way it works is that you can add stuff to your Instapaper account from anywhere pretty much, via a link on the web or via many apps that have a "Send to InstaPaper" feature (Twitter's iPhone app for example has it).
Then when you have some time you pop open the app and see all the stuff you've collected for reading later.
The killer features that Instapaper offers are that the pages are saved in a format that is easy to read, it strips away all the irrelevant stuff and leaves you with a version that's optimized for the iPhone and iPad screens so you can focus on just the relevant content. Instapaper also downloads to your device everything you've added to your Instapaper account so that you can read it whenever you want, even when you're offline on a plane, subway, or have an iPad that is Wifi only and not connected to the Internet at the moment.
The app developers really focus on developing features that make reading easy, from an auto-scrolling feature, dark mode, preview links in the built-in browser without leaving the app, and more.
Instapaper is relatively expensive for an app, it's $4.99 (which is less than a burger costs, but for an app that's considered a lot) and is a Universal app for both your iPhone/iPod Touch and iPad.
It really is one of those essential apps you need to have on your iPhone and iPad. It's been highly praised by different magazines and pretty much all the user ratings there are 5 stars.