This already exists on Wikipedia.

Under preferences, select the Gadgets tab and enable "Navigation popups".

When hovering over a link in a Wikipedia article, a small popup will appear, in addition to some metadata about the link, the first paragraph of the article will appear, including links that may appear in that paragraph, which can also be hovered to make another popup appear.

Incidentally, this was what my diploma thesis was about. The basic idea was to have a single »text« that contains lots of possible branching or expansion points, depending on certain criteria. Depending on those criteria you'd get a expanded or contracted text to read that would be tailored to what you already know or are interested about. Altering the text in small parts (like [−1½] mentioned in another comment – I found that one much later, though) was one part of it; inline expansions if necessary or wanted were a possible UX enhancement I thought of (avoiding a completely static text where you'd have to tell the engine everything beforehand).

Use cases I thought of were mainly adjusting texts explaining things (e.g. Wikipedia, school books, etc.) to the already existing knowledge of the reader. So that an article explaining a concept could look radically different (and going into increasingly more detail) depending on what the reader already knows. One proof of concept I created was adjusting the German Wikipedia article on Turing machines to three different levels (school, 1st semester CS student, 4th semester CS student) [75.3]. What each level does is either explaining things differently or leaving out parts altogether (no need horrifying a pupil with formulae). So my main focus was on providing something that reads well (expanding things inline still incur a context switch because they're not part of the original narrative) and finding a way how to model such things. Nothing automatic because a clear semantic model is needed for that to work.

Thesis can be found at [0.046], it's in German, but the abstract is in English too. Just in case someone might be interested in that.

[−1½] http://www.telescopictext.com/ mentioned by https://news.ycombinator.com/item?id=7602335

[75.3] http://hypftier.de/temp/turing.html – sorry, it's in German, but Google Translate seems to work fine.

[0.046] http://hypftier.de/temp/Diplomarbeit.pdf

Wikipedia currently has a Beta feature name Hovercards

You can enable it here

https://en.wikipedia.org/wiki/Special:Preferences#mw-prefsec...

About popups/tooltips/hovercards: I considered this approach, but decided to go with this sort of "inline" expansion for the following reasons:

1. A popup obscures the original text. This interferes with context, albeit admittedly to a much lesser degree than full-blown navigation, but still.

2. Multi-level popup hierarchies just don't look good, in my opinion.

3. You must dismiss a popup to continue, whereas with inline expansion you can just as well keep the expansion and continue reading.

4. The hover approach doesn't work as well for touch-devices (i.e. without a mouse).

Tree-style tabbed browsing makes tree-traversal style web browsing far more tractable.

Sadly, Chrome doesn't have a tree-style tabs mode, nor can it be provided by the existing Chrome extension format. There are a number of tree-style tab extensions for Firefox (e.g., "Tree Style Tab": http://piro.sakura.ne.jp/xul/_treestyletab.html.en).

There are any of a number of changes to the browser model I'd very much prefer aimed at information management, as opposed to the web-applications centric focus of the past several years.

In an interesting departure, Kobo advertised among the features of its (Android-based) tablet a web browser which simplified pages to an easy-to-read view. Based on present pre-loaded apps bundles, it looks as if that was the Pocket browser, but I still find it interesting that this was pitched as a benefit to a largely nontechnical, literary audience. It certainly reflects my own growing dissatisfaction with present-generation browsers.

Any article on an advanced topic is going to be difficult if you lack prerequisite knowledge, no matter how fancy the cross-reference ui.

I find the Google Dictionary plugin is pretty good for reading wikipedia like this...

https://chrome.google.com/webstore/detail/google-dictionary-...

Similar, but apparently "one-way": http://www.telescopictext.com/

While the suggested feature would be a improvement, the real goal imho should be that each Wikipedia article can be read and understood by itself, without the need to go on a recursive yak shaving expedition through other articles first.

The American Institute of Mathematics has been promoting "knowls", which is a very similar idea and implementation: http://www.aimath.org/knowlepedia/

Rob Beezer's free open-source linear algebra book uses these extensively to provide more details in proofs and in exposition. It's very nice. For example, click on the underlined blue text at http://linear.ups.edu/html/section-SSLE.html

Wish granted: http://wikiballoons.tomodo.me/wiki/Main_Page

I also made a (by no means complete) POC more simmiliar to your animation which you're welcome to fork and improve: http://en.wikimore.tomodo.me/wiki/Main_Page

In general, whenever you want to improve a website - Tomodo is the place to go (http://tomodo.com/)

Since my primary language is Dutch, it's easy for me:

If I want a short article, read the Dutch version. If I want too many details, read the English version :)

I thought this was a really interesting idea and tried implementing it. You can check out the demo here:

http://xuanji.appspot.com/static/wikipedia.html

Note that the "sinusoidal wave" link isn't working, as it redirects to "sine wave"...gotta work around that :(

If you want to read/modify the code send a pull request to github.com/zodiac/xuanji.appspot.com/, the commit which implemented this is https://github.com/zodiac/xuanji.appspot.com/commit/872b40dc...

welcome to Ted Nelson's original idea of hypertext. further information here: http://en.wikipedia.org/wiki/History_of_hypertext

I like it a lot, my use of wikipedia often leads to a bunch of opened tabs and a lack of focus on what I was looking for in the first place (which might also be a great thing depending on your mood).

If you have a mac, you can right click on any word and choose "Look up in dictionary". The dictionary pulls definitions from it's internal dictionary and wikipedia.

I use the 'wikipedia quick hints' chrome extension and it works really well for me. It works kind of like the navigation popups already mentioned - but links inside the modal can also be hovered over, 'recursively'.

https://chrome.google.com/webstore/detail/wikipedia-quick-hi...

I prefer popups (floating elements) instead of altering the flow of the document. The continuous re-flow of the document is distracting.

I want my computer to get a concept of what I know. It should then gray out stuff I know and linkify stuff that might be new to me. Semantic Web is the key word here. Decades of research went into that but this magic tool still is not anywhere near yet.

Neat idea, but the article also made me discover Basic English and its 850 words. Didn't know about that, I think that should be mentioned when you learn English.

Does anyone know of similar general purpose word sets for other languages?

Take a look at https://github.com/sanketsaurav/easywiki which do exactly what he proposes and work on other websites when hovering wikipedia links!

Didn't Ted Nelson suggest this sort of in-situ display for transclusion in Xanadu?

Maybe the prose could be written to assume less knowledge and reduce the amount of other material needed for most people to understand? Alternatively as a user preference the prose could auto-include the meanings of some terms?