Difference btw rel="nofollow" & putting urls in robots.txt

I've been going through all my sites and using nofollow's all over the place, but I've been wondering lately what the difference is between using the rel="nofollow" and putting the url's in the robots.txt file?

If the url is in the robots.txt file will it still receive PR juice?

Blocking the urls from indexing in your robots.txt prevents crawlers from visiting them at all, or listing them.

Ref=nofollow passes no link juice, but the urls may get followed and indexed anyway. Yahoo follows them.

Danny Sulivan says "Google WILL follow nofollow links in the sense that if someone else links to a page without using nofollow, then Google might find the page that way. Nofollow on one link to a page doesn't somehow cause ALL links to be off limits. "

I was just thinking about this, and it's an important thing to use a nofollow, but not to block the url with the robots.txt if you've got pertitiant info on the page, and/or if you've got sitelinks or plan on getting them,

ex: you might not want to waste your PR on the "Driving Directions" page, but you still want to see that sitelink show up in your listing ;-)

Thanks again

how do you block google following an outgoing link in your robots file?

Can someone show me the code?

No way to disallow indexing or following of an outbound link in your robots.txt file. Your robots.txt list files or sections of your site you want the robots/search engine crawlers to stay out of and not index.

User-agent: *
Disallow: /real-estate-articles/


Wow, wouldn't that be great if you could disallow outgoing links?! List all your competitors links and disallow indexing of them. heehee

The robots.txt is really just a way to make it so the spider doesn't index admin pages, and in one of my personal instances: pages that let a user add a review. But the more I think about it, the more I realize that that's all you should really put in there, and then just use the nofollow for everything else, the way that seochat has done here.

Not just admin pages. How about member's only areas? What good is it to charge a fee, or to only display content after user becomes a lead, if they can view the same content viewing Google's cache? There are many area's you might want to disallow indexing for.

cgi bin
drafts
private
duplicate printable versions
iframes content, that have no navigation
members only