bogdan

Embeds are needed to embed video from youtube or to embed Google Map or just to embed content from external page. 
WordPress removes embed when you switch from “HTML” to “Visual” tab because of the security reasons. 
So you can embed object code using this shortcode <code>[iframe src="http://player.vimeo.com/video/3261363" width="100%" height="480"]</code>.

iframe to embed

Embeds are needed to embed video from youtube or to embed Google Map or just to embed content from external page.

John Godley

PageView is a plugin that will display another web page inside the current post. This is achieved with the use of an 
iframe – an HTML tag that allows a webpage to be displayed inline with the current page.
To use:
<pre><code>[pageview url="http://urbangiraffe.com"]
</code></pre>
Optional arguments:
title = A title to show under the iframe 
desc = A description to show under the iframe 
width = Width of iframe, in px or % 
height = Height of iframe, in px or %
<h3>Documentation</h3>
Full documentation can be found on the <a href="http://urbangiraffe.com/plugins/pageview/" rel="nofollow ugc">Pageview</a> page.

PageView

Insert an iframe and display an external website directly in a post using just a shortcode.

iframe to embed vs PageView