Why Slack is so Successful | Pricing Page Teardown
It's an experimental feature (Beta stage). The concept of Pocket, instapaper and other bookmarking apps to load the website inside the webapp is used here.
If the below webpage doesn't open, Then use this link:
If this embedding the webpage violating any of your website policies. Then contact me at email@example.com.
I will take out your content and give actual links to your website.