If you have a large website with hundreds to thousands of pages such as large scale ecommerce sites then for sure it helps. It helps with users being able to navigate more easily as well as search engines with crawling and indexing.
However as with category and tags its a good idea to use nofollow attribute, especially if you are attempting to funnel link juice to other pages. Keep in mind when you have links on your page whether its outbound or internal the link juice will be diluted (the more you have), hence if you are funneling juice from post/page to another then its worth considering how to maximize link juice flow.
SEOPub - Interesting points! ... Appreciate your inputs on the following:
1) If a page has say 4 links, 2 of which are nofollow then my understanding the link juice will be distributed between the two dofollow links? Are you saying the nofollow links gobbles up a proportion of the link juice to a blackhole? If that is the case then what is the point of nofollow? For example sites which display ads most often use nofollow links, however based on your comments it seems to me that the use of nofollow will have an impact...
The example you use is how it worked before 2008. In 2008, Google changed how they handled nofollow. Before that, the linkjuice would be divided up among the links that were 'dofollow' (for lack of a better term because there is no such thing as a dofollow tag) only. So what marketers and savvy SEOs started doing was using nofollow for PageRank sculpting. They could effectively control where linkjuice was going. Google got pissed, and decided to change it so that linkjuice now flows through all the links on a page. In the case of nofollow links though it does not pass onto the pages being linked to. It just vanishes more or less. So when you nofollow internal links, you are actually how the linkjuice flows throughout your site in most cases.
It depends. If they are putting a nofollow tag on internal links, then yes. If they are putting a nofollow tag on external links, the linkjuice is flowing either way. It just is not getting passed on to those external sites. It cuts down on spamming, so it is probably a good practice for external links.
Further if this is the case then what is the impact i.e. percentage values etc? It seems from your reply it is hugely significant despite common consensus that nofollow does not pass link juice with G ignoring the links... Can you provide any references to tests/resources which proves that nofollow does indeed pass link juice to a blackhole???
2) Regarding duplication issues such as category, tag pages etc... My understanding is that rel="NOINDEX, FOLLOW" is the way to go with avoiding duplication issues and hence why I assumed this can also apply to breadcrumbs should one really want to use them with using nofollow forming a combined approach when considering conserving link juice...
That said I personally dont use breadcrumbs but I figured if you really want to use them then at least one should consider the impact that would have with internal linking structure... Surely in that case nofollow setup is better than dofollow... So in the case of large sites using breadcrumbs what do you recommend given your strong disagreement to use nofollow... I assume you recommend dofollow setup in that case...???
Simply put, there are very few cases I can think to advocate ever using nofollow for an internal link. You are shooting yourself in the foot. Personally, I almost never would suggest using breadcrumbs. For really large sites, there is always a little give and take when it comes to SEO versus the user experience.
If you need breadcrumbs on a smaller site to help your users, that means your site structure and navigation sucks in my opinion. You have bigger problems.
As far as duplication issues go, canonical tags is the best way to deal with those.
BTW - Interesting idea regarding the use of iframes... Why stop there wrt breadcrumbs? Perhaps one should also consider using it with a sites menu navigation (top/bottom bars) etc... Indeed that has got me thinking how one could apply/amend themes with such a concept in mind etc...
There are a lot of tricky ways you can use it for conserving linkjuice. I don't want to advocate using it on your navigation menu across the board. There are too many novice marketers here that are going to get confused and do more harm than good. In my training course though, we have had some good discussions on how you can use this sort of idea to conserve linkjuice within a silo without compromising the user experience. Hugely effective.
As you might know it is a process of linking your webpages. So, I don't think it will help the website SEO in any manner. It can only be helpful for the visitors of the website. So, it is not necessary to use breadcrumbs.