There are browsers that support MathML and there are browsers that support Unicode and most of the notations used. These technologies should be taken advantage of when possible. For a site that claims to be smart enough to understand natural language, I’m sure they could make their algorithms smart enough to drop to plaintext when there are no typographical issues. They already use plaintext with images quite successfully on their sister site MathWorld. I see nothing inconsistent about that UI. The value of having directly copyable text is huge from a user experience point of view, especially for a system where data is meant to be taken out.

On a sidenote, I really don’t understand this “Export to PDF” thing. Are they trying to reimplement the browser on the server side? This is something 99% of browsers and OS’s in general already support via the Print functionality (it might be XPS or PS depending on the system). It seems like yet another service that needlessly tasks their systems.

1. Subscript and Superscript messes up line height. And there are a lot of these, in data, H2O, H2SO4, Na+, Cl+.
2. There are many mathematical formulas, that are not on the same line. Usually when there are large number fractions/division where both numerator or denominator may be a large formula, or even another fraction.
3. Special characters used in formulas, although we can use all these ASCII codes and display them with the &#—; format, we are not 100% sure they will render well depending on the character sets installed on each browser.
4. Many images may need labels and might be positioned in weird ways.

Overall, I think it is just easier to make them images or use flash than use tons on pixel positioning/controlling words by the pixel, using tons of floats. Now if the system works and runs fast, then I might as well use it for everything else to be consistent for the whole system.

However, there’s no issue in copy/pasting from a Wolfram results page and pasting into something plain text. The data is clear as day. Try it. It can be scraped.

That said, you all make some great points.

I especially think Paul Ford’s point that the real value of Wolfram|Alpha may be is its underlying organization and not the data itself a very strong counter to whether or not they may be concerned about screen scraping.

Also as Joe mentioned, scraping an image for its content would seem to be a harder task than just grabbing the jsonArray associated with every image.

So why render text? I’d say this could just as likely be a case of “not invented here” where the thing NIH is “the world wide web.” Mathematica has been around forever and has its own way of doing things. They know how to render exactly the way they want, and a certain typographic awareness is obviously boiled into the company’s DNA (the production process on New Kind of Science being a prime example). Rendering to HTML as a target (which likely could be done with a combination of JSMath and eeeevil stylesheet tricks as Google does in its PDF-to-HTML converter) probably looked bad (see how Sage, a competitor to Mathematica that’s open-sourced and web-driven, does it to see how many tricks are necessary–math is [sometimes] rendered to image there too, and Wikipedia also renders its math using LaTeX).

What confuses me most is that Alphram’s output is not clickable. If you’re going to get all GIF on me to allow for absolute positioning, bring back the USEMAP and let me click on key terms to auto-propagate search queries; this would DRASTICALLY lower the learning curve so that I could see which kinds of queries were possible or not without all the guessing. As to Joe’s pt. on the screen-scraping–yeah, Ajax is evil this way and hard to SEO in many cases. That said given the open-source nature of many HTML/JavaScript engines writing a spider is probably possible if non-trivial.

Also, the alt and title of the img tags you refer to have equivalent content that can be scraped just as easily as in-line text. The bigger issue for screen scrapers is that if you disable JavaScript you get the message “To see full output you need to enable Javascript in your browser.” To do the screen scraping of this site one would need to be able to execute JavaScript to make the network calls Wolfram Alpha makes.