iFrame vs Great Search Engines
An IFRAME is an HTML tag used in web design that allows a webpage to be displayed in a frame within another webpage. Inline Frame (iFrame) is the content cut into web page which allows visitors to view another pages on your website or off your site without reloading the entire page.
Someone told me that iframe link will be indexed by search engines as same as the pure HTML link.
In the SEO ways, iFrame usage is problem against search engines for many reasons.
For one reason, whenever search engine robots spide the contents within iFrame, they usually link to iFramed page instead of the page they are displaying.
It means searchers are delivered to a page without site navigation or to the hidden page. It did not encourage search engine robots to crawl and index the such iFrame pages.
Does iFrames Cause Problems with Search Engines?
Yes, of course.
It take those contents and links to other pages. And your link building will be harder than with other webmasters and website owners. You should active the iFrame pages first, if you want your iFramed pages are friendly with the great search engines.