Nope. Iframes are the devil's work. Nope.
I think you might be talking about copyright infringement, and in that case don't do it; Leafypiggy and x10 will shun you; and
you may be sued for breach of the TOC; and
x10 may be held liable for not taking action against you (failure to mitigate) as soon as they are made aware of the infringement. (this statement is legal ed., not legal advice)
<!--#include src="your_page.html"---> and change your page to an .shtml
the problems are the extra strain on the server and you can't use a server side include as a target like you can with an iframe.