What does Unrestricted Web Access mean in iTunes Connect

Question

When you are submitting your app to Apple app store, there is a section named "Rating" where you should rate your content based on the chart and identify how frequently the content appears.

There is one option called "Unrestricted web access" which there are no further details available about this on the Internet nor iTunes Connect Developer Guide. All you can find everywhere is:

Select Yes if your app allows users to navigate and view web pages, such as with an embedded browser.

What does this mean? Does this mean your app can open links in embedded or Safari browser? Or does this mean your app features a browser where users can enter URLs and navigate through the web unrestricted? Because saying yes to this question will make your app 17+!

If this means opening links from your app (Safari or embedded), how come other apps that have embedded browser capability have 4+ rating (like Twitter and Facebook)? As it can be seen in screenshots, there is no way to select this one and not be rated 17+

Update: My app was approved with embedded WebView (TOWebViewController) with the answer "No" (4+). As the answer mentions, any way you let users navigate through the internet such as dynamic address bar that means it should be "Yes" (17+) because it is not possible to do Parental Control on your WebView.

Update 2: Since the release of iOS 9, Apple has introduced SFSafariViewController which is a way of opening any URLs on the internet. This feature also has an address bar but read-only. So users can't surf the Web without parental control. It also inherits content blocking from Safari (ads, explicit content, etc.). I am highly positive by using SFSafariViewController in iOS 9 or above you still can choose 4+ as the device with parental control can't open any URLs anyway. (Let me know if I am wrong)

Update 3: Twitter now is 17+ based on the followings:

You must be at least 17 years old to download this application.

Infrequent/Mild Profanity or Crude Humor

Frequent/Intense Mature/Suggestive Themes

Infrequent/Mild Sexual Content and Nudity

Update 4: It is possible to use Twitter content inside your app without inheriting its rating (17+). My app is displaying Tweets, but since the users are verified and trusted public figures I could go down to 12+:

Infrequent/Mild Sexual Content and Nudity

Infrequent/Mild Profanity or Crude Humour

Infrequent/Mild Mature/Suggestive Themes

Answer 1

It means that a user of the app can access any URL. The issue is parental controls. If the parent has restricted web access an app that allows unlimited access, that is access to any site the user chooses then the parental controls are subverted.

Once Apple provided parental controls that caused a ripple effect on the capabilities of apps and also required Apple to review all apps for parental control violations. It also means that alternate app stores could not be allowed, they could contain apps that did not properly honor parental controls. Hence:"The Walled Garden."