Originally you asked about "Embedded Frames", which implies HTML iframe tags. Those don't work and are disabled for a reason - you can embed almost anything inside those from external sites, and that causes a TON of security risks.
In comments, you referred to this question as an example of what you're looking for. Basically, what that scrolling block of text is is just a very large block of code-formatted text. The posting system will automatically put long blocks of code-formatted (indented) text into a scrollable box in answers and questions so a single post doesn't take up a huge length of the page.
This only works in questions and answers. You can do preformatted text in comments by surrounding single lines of text within backticks (`), like this:
`This is preformatted text.` becomes This is preformatted text.
