I have reposted this question on Software Recommendations.
I'm looking for a web app for tutoring math remotely to high school and junior high kids that ideally has the following:
Build in graphing. The exemplar for this is the application Geogebra, which not only allows graphs, but also has a table view, sliders, and animation, and is scriptable. Indeed, a networked multi-user large canvas version of geogebra would meet most of my requirements.
Built in drawing tools. At a minimum: freehand, line, polygon, text, and eraser. Drawing tools should be vector based and not pixel based, so they can be easily moved and edited.
Editing tools: It should be possible to change stroke, fill, fontsize, font color, location, rotation.
Additional desirable tools: Marque select, group, layer, lock, bezier, arc, fill
Desirable Stationery: Various kinds of lined/graph paper including graph paper with index lines (heavier lines) Polar coordinates, log, log-log etc. This could be done as a PDF or GIF image layer, or best, would be as a fill you could position in a rectangle.
Multipage canvas. Application should not be limited to a single screen.
Persistent sessions. I want to come back tomorrow and see it how I (or my partner) left it.
Multiple simultaneous editing. I should be able to edit one thing while another user is editing elsewhere. This may mean that the other user may be on a different page from me. As an adjunct, a way of seeing what changes were made while I wasn't looking at a page would be useful -- deleted items in pink, and new ones in green maybe.
Handwriting recognition for math. This one is tough. MyScribe MathPad looks good, but it's online demo only does a single equation at a time. webFluidMath has one approach, but it's not really ready for prime time. It took me 6 attempts to get ax^2 +bx + c = 0, and I never was able to do a 2x2 matrix. In principle I could create the equation in one app and paste it in, but this makes editing difficult, and gets in the way of teaching the derivation of a theorm or equation.
A keyboard approach is an acceptable alternative. The best of these I've found so far is Lyx, which has a combination of keyboard and mouse selection. MathML requires lots of extra () to be added. FrameMaker's equation editor got one thing correct with the use of a space character to exit one level of nesting. Lyx does this too. I do NOT want to type full TeX.
For this reason I'm not considering various TeX enabled chat room programs.
Handwriting recognition is desirable, but not required. I will live with my scrawls if need be.
Compatible with iPad. Apple limits script functionality on their platform. Notability is has a decent approach on the ipad. You can draw, you can bring in PDFs and annotate, add images, and draw on them etc.
Note that none of the applications mentioned (Geogebra, Mathpad, webFluidMath, Lyx, Notability) is collaborative software in the sense that multiple people can use it in real time, seeing the changes that the other party has made with only minor delays.
The use of 'networked' here means Internet -- The two parties will NOT be on the same LAN. I do not care if it is application based, or web based, except that if the former, it has to run on iPad, Windows >=XP, and Mac >= 10.6 (Snow Leopard)
TeamViewer is one example of a desktop sharing app. This is one approach, but only one user can control the mouse/keyboard at a time, and whatever app you are using is limited to the present screen. Teamviewer is clunky to use on a network with significant latency (over 100 ms)
Real Time Interactive: (RTI) All parties can write at the same time, on different parts of the canvas, possibly different screens, using different tools. Delay between updates measured in seconds. Turn Based Interactive: (TBI) Only one person can draw at a time. All people see the same screen/zoom/view. TeamViewer works like this. Shareable: One person can create a document, publish it to some form of cloud repository, then other people can edit it. Google docs works like this most of the time. Presentation Other people have read only access, possibly in real time, possibly saved as a recorded session.
Persistent A session can be stopped then later resumed even if there is a period when no one is using the document. Transient Session vanishes when creator or last client quits the application.
Pixel based graphics (PBG) Tools change the color of pixels on the screen. Generally impossible to edit. *Vector Graphics (VG): * Entities have individual existence, so you can move parts around after creating them, and change attributes such as line width, size, stroke color and fill.
Existing product limitations: Most of these evaluations were done quickly, and stopped once I ran into 2-3 items not on my wish list. Some of these may be useful for other purposes.
iDroo VG, RTI, limited drawing set. No math. Can drag and drop images onto the canvas, or into a column on the edge, where they are stored as thumbnails. Active development. Most usable whiteboard of the lot. Best for tutoring.
VMT This is the virtual math team project at Drexel university. Their Java app can run sharable whiteboard or geogebra in a tabbed interface. Whiteboard is clunkly and somewhat limited. GeoGebra has a HTML5 Canvas version in Beta. Worth Watching. Geogebra tabs can be pre-loaded with a Geogebra worksheet. Best for instructing a class.
Baiboard is one collaborative app that has possibilities. It's sketch + PDF annotate with the ability to save snapshots at any time. This is a good example of the collaboration aspect. The drawing tools are weak. Only available on iPad and Mac, and the Mac version is much more limited. Persistent, RTI
Groupboard: Limited VG: Objects can be moved, but not modified, RTI. Math is limited to pasting from a limited symbol set. http://www.groupboard.com/demo/math.shtml
Groupworld: This is from the same people as Groupworld. Same problems.
Board 800: Limited VG: Objects can be moved, but not modified, RTI. Limited drawing set. No math. Multi page.
Tutorsbox: VG, RTI. Objects can be moved but not modified. Limited tools. Line, circle, square. Function grapher. Has wysiwyg math editor, but it operates in a modal window, which makes deriving something tricky -- you cannot see the previous line. https://tutorsbox.com/en/ Plans start at $9/month
Show me: Pixel based. No editing. P.o.S.
iDroo: VG, RTI. Limited drawing set. Pencil, line, rectangle, elipse, text. No color. No math. Objects can be moved and rotated. Marque select to move multiple objects. http://www.idroo.com/
RocketBoard This is an actual white board sharing app: You write on a whiteboard using standard markers, and the app corrects for perspective, and adjusts contrast. Slick way to lecture. BUT... * No way to import material, or graph paper. * No way for me to annotate another person's work, or for them to copy/paste from my work except as a bit map.
AWW A Web Whiteboard: Pixel based, no erase except clear, 4 colors. P.o.S.
Scribblar: $9/month. Free plan doesn't have many features. Untested.
I have asked for recommendations elsewhere on StackExchange but have not received good results.