In my understanding, a webapp is essentially a "desktop-like" application for the browser, i.e. something like gmail or an online paint program, something that is interaction driven, will probably use websockets for giving a realtime feeling, etc. A website is the traditional static content, like a blog or a news site. Obviously, these are just relative and its a scale so there cross-over and sometimes its hard to define in exactly which category an app/site falls.

quite different-- Web app, think Google Docs/Sheets.

Web site, think blog, information landing page, or even web store product page(s).

Web app is highly interactive (may or may not be an SPA single page app), relying heavily on javascript for UI events, saving/fetching application state, remote datasets, and sometimes making use of modern HTML5 browser features.

Web site is displaying information and is just augmented with some javascript mostly for improving the UX or attaching analytics/social plugins etc.

Given that this distinction is entirely subjective (no-one will be able agree on what a test that pigeonholes pages as a 'site' or 'app'), how is it a useful distinction?

It may not be a useful distinction, but it's useful to have a sense for where on the continuum the thing you're building sits, in order to make technology and architecture decisions. If you're building something more "website-y", it should probably have an architecture that optimizes for search-ability and static caching, whereas if you're building something more "webapp-y", the architecture should probably optimize interactivity and dynamic updates. Most things end up somewhere in the middle, but leaning one way or the other.

I don't think anyone is trying to partition projects into disjunct sets. It's more of a continuum. I think the idea of "app-iness" just captures the interactivity and statefullness of an experience. Incidentally, that additional complexity is exactly what the Web technologies were initially ill-suited for and what frameworks were built to help manage.

Is a "simple website" and a "complex website" a better distinction in your opinion?

Thus I am a complex website engineer. It sounds ridiculous. The webapp developer is domain knowledge wise closer to traditional "application development" than to traditional "website development".

Are sites like vox or gawker considered websites or web apps? Their custom CMS is quite expansive. How bout NYTimes? Is YouTube a web app or a web site? I'd be curious to know some examples on either side. Preferably several closer to the line but on one side or the other rather than far away.

I think you answered your own questions.

I totally agree web site and web app are used interchangeably sometimes -- I was just answering the op as to how I and many people I know classify them and their differences as they relate to the topic of the article, javascript.

For me a web app is an HTML5 web page, that has its interaction logic coded in JS and presentation is done by altering HTML5 DOM and where JS uses REST to send/receive data.

In other words as someone else noted, it is a sandboxed application with

sandbox execution environment == browser IO == REST UI = HTML5 DOM manipulation of the same page

A website (or server app) is a series of HTML5 web apps or HTML5 static pages (JS-less web apps) with navigation logic and inter-app state living in a server app.

Why the emphasis on REST? Websockets tend to be easier for complex applications.

It's not entirely subjective.

I'd say

web sites are content centric and made for consuming it.

web apps are interaction centric and made to "do" something.

I agree. Consumption v. production is a good way of looking at it.

Note that this definition means that certain pieces of software could be considered either "sites" or "apps", depending on how they're being used.

For instance, blog software like Wordpress would be a "site" for the readers, but an "app" for the person who writes the posts.

A "product" can consist of different parts.

One part is an editing software/gui and one part is a reading software/gui. Both working on the same data.

Since both are used by different kind of users, I would design them as different programs (one a site and one an app).

It's been around for a long time now actually.

Web App are application like website.

So instead of traditional application/program such as Quicken we got Mint.com now. It makes application OS agnostic now too.

Web sites are bunch of pages that are hot link or connected via URL. Think of the old days of geocities, xoom, tripod, etc..

A while back there was a lot of chat about "single page web applications" - I suspect people have simply condensed that mouthful into "web app".