In my case I would like to . . . .
1. place a file on my own site which contains links to all the sites I produce.
2. place an iframe containing this file in all the sites I produce, so if I have 10 sites they now all linkshare with each other.
so my Query is will the search engines identify the links on each site as external links from that site or will they only register those links as coming from the site on which they are hosted ?
any advise is appreciated and I hope to be of some help to someone on here someday !
I don't think the business case has been made for using iFrames to manage search engine optimization priorities, but I'll admit that a few people (especially on Search Engine Roundtable, which linked to this discussion) have shared some intriguing ideas.
The question really comes down to, what are you trying to accomplish?
iFrames would be a very poor choice in my book for hiding something from search engines. You can block them from being crawled in robots.txt, in which case I would use folder/file names that were NOT keyword-rich to reduce the chance of the uncrawled URLs appearing in important queries.
You can embed robots meta directives on them like "NoIndex,NoArchive" and possibly use them for boilerplate or "sitewide off-site" navigation that you don't want to pass value through, but it might be deemed a spam tactic at some point in the future.
iFrames are being crawled -- and HAVE been crawled -- by rogue sites that take the content and publish it on their own pages. This is a form of scraping that may have arisen from people trying to think of ways to show the search engines "unique" content. It's a spammy tactic and I have no idea of how well it works, but relying extensively on iFrames may entail some risks where your content is used against you.
For now, at least until more people experiment and share the results of their experiments and observations, you should view iFrames as useful for deploying widgets and other content that cannot be easily optimized for someone else's benefit, and you should use practices that help ensure your iFrames don't appear in places where you don't want them to appear (as much as you can control or influence that).