Selected answers from the Dumb SEO Questions G+ community.
Chris M Cloutier: Whats the deal with iframes? I hear people say they're bad but we embed YouTube vids all the time. ;Is that bad for SEO too?
Tim Capper: In short a search engine cannot crawl what is in an iframe.
If you are embedding a youtube vid, map or some other piece of content onto a page, a search engine cannot crawl this, but i would not say that it is bad for SEO as it increases the user engagement, experience on page and ads to the content on page.
If you had a new page and only had an iframe on page with zero additional content, then that would be bad SEO.
Tony McCreath: I'd argue that search engines (at least Google) can crawl what's in an iframe, but it makes their job difficult. e.g. Is the iframe content part of the page or should it be treated as it's own page?
A mute point for YouTube as the content contains nothing directly to index. ;
With video you can add semantic markup around the embedded video to provide more information to the search engines on what the video is about:
Chris M Cloutier: Thanks ;schema is something that still totally confuses me. ;So I've just overlooked it but I know that's a mistake. ;Thanks for the link.
Kalpesh Bharankar: if you put embed YouTube vids on your site, google will ignore because of iframe, but if your video is properly optimize from SEO perspective Google will certainly show your video in SERP for any perticular query or keywords.
Chris M Cloutier: I'm not really worried about the video itself showing in serps.(except from YouTube) ;I just don't want the embed to kill the post.
So, if I write a great post and embed a YT video I don't want the iframe to keep my post from ranking. ;
I'm probably going to switch to using Vimeo for my embeds anyway. ;That way I don't have to worry about cannibalizing my YouTube content. ;Thanks ;
Tim Capper: ;the content on the page will still be visible, it is only what is in the iframe that is not visible and that would be only the youtube url.
Chris M Cloutier: ;Yeah that's what I was trying to say. ;Basically when I embed YT video I don't care if it gets ranked. ;Later I might but I won't use YT then.
Tony McCreath: I think most video embeds use iframe now. I think it helps them provide better compatibility via supporting both flash and html5.
It's not an issue and something you don't need to worry about.
Dave Elliott: As long as you don't want the content inside to be indexed then there is no harm in iframes, if it is stuff you want to rank to rank for, then you are asking for trouble