Which one is bad? External - when someone adds an incorrect link to your site, maybe does a typo when linking to an inner page. This page never existed on your site, google shows this as a 404 in Webmaster tools. Internal - a page existed, google indexed it, and you deleted it and didnt add a 301. Internal ones are in the webmaster's control, and i can understand if google gets upset if it sees a 404 for a URL that existed before, however surely "externally created" 404 shoudnt cause any harm cause that page never existed. And someone has inserted an incorrect link to your site.

On my wordpress shopping cart plugin, I have three pages /account, /checkout and /terms on which I have added “noindex,follow” attribute.   But I think I may be wasting link juice on these pages as they are not to be indexed anyway, so is there any point giving them any link juice? I can add “noindex,nofollow” on to the page itself. However, the actual text/anchor link to these pages on the site header will remain “follow” as I have no means of amending that right now. So this presents the following two scenarios –   No juice flows from homepage to these 3 pages (GOOD) – This would be perfect then, as the pages themselves have nofollow attribute.   Juice flows from homepage to these pages (BAD) - This may mean that the juice flows from homepage anchor text links to these 3 pages BUT then STOPS there as they have “nofollow” attribute on that page. This will be a bigger problem and if this is the case and I cant stop the juice from flowing in, then ill rather let it flow out to other pages.   Hope you understand my question, any input is very much appreciated. Thanks