How Google treat internal links with rel="nofollow"?

[CommercePundit]

Today, I was reading about NoFollow on Wikipedia. Following statement is over my head and not able to understand with proper manner.

"Google states that their engine takes "nofollow" literally and does not "follow" the link at all. However, experiments conducted by SEOs show conflicting results. These studies reveal that Google does follow the link, but does not index the linked-to page, unless it was in Google's index already for other reasons (such as other, non-nofollow links that point to the page)."

It's all about indexing and ranking for specific keywords for hyperlink text during external links. I aware about that section. It may not generate in relevant result during any keyword on Google web search.

But, what about internal links? I have defined rel="nofollow" attribute on too many internal links.

I have archive blog post of Randfish with same subject. I read following question over there.

Q. Does Google recommend the use of nofollow internally as a positive method for controlling the flow of internal link love? [In 2007]

A: Yes – webmasters can feel free to use nofollow internally to help tell Googlebot which pages they want to receive link juice from other pages
_
(Matt's precise words were: The nofollow attribute is just a mechanism that gives webmasters the ability to modify PageRank flow at link-level granularity. Plenty of other mechanisms would also work (e.g. a link through a page that is robot.txt'ed out), but nofollow on individual links is simpler for some folks to use. There's no stigma to using nofollow, even on your own internal links; for Google, nofollow'ed links are dropped out of our link graph; we don't even use such links for discovery. By the way, the nofollow meta tag does that same thing, but at a page level.)

Matt has given excellent answer on following question. [In 2011]

Q: Should internal links use rel="nofollow"? 

A:Matt said:

"I don't know how to make it more concrete than that."

I use nofollow for each internal link that points to an internal page that has the meta name="robots" content="noindex" tag. Why should I waste Googlebot's ressources and those of my server if in the end the target must not be indexed? As far as I can say and since years, this does not cause any problems at all.

For internal page anchors (links with the hash mark in front like "#top", the answer is "no", of course.

I am still using nofollow attributes on my website.

So, what is current trend? Will it require to use nofollow attribute for internal pages?

[CommercePundit]

Even if you don’t want a page to rank,

Page rank is ranking factor? I don't think so... I am not opposing you but in my category there are many websites which are performing well with low page rank. And, high page rank website is still at bottom.

Have you any idea about it?

[AlanMosley]

First I mast sure you understand, that no-follow still leaks link juice, it just does not pass it to the linked page.
there was a time where you could stop leaking link juice by using no-follow, but not any more.
So using no-follow’s is generally not a good idea. If you do you are wasting link juice. Even if you don’t want a page to rank, you are better off letting the juice flow and have a link on the linked to page pointing back to your home page or any other page you want to rank.
As for no-follow and the fact that Google still follows. They don’t follow though that link, but they may get to the page from another link, or they may already have the url in their index.
You can put a no-follow meta tag in a page or a no-index. A no-follow meta tag, will allow Search Engines to crawl the page, but will not give link juice to any pages you have linked from that page, but as I stated, you will not keep the link juice, it will just evaporate. A no index will stop SE’s from indexing that page