After watching teachers and students use the K12LTSP system here in 
Atlanta, in detail in elementary and now middle school, my vote for 
the killer app/use case to make OpenSource become truly mainstream in 
education is...drum roll...
Netbooks capable of also running as thin clients over wireless LAN
Here's why: netbooks, especially when they get below $200, are 
designed for the key applications for education: web access, office 
suite (mainly word processing, presentation, and spreadsheet), and to 
a lesser extent, image manipulation.  We set up a MAC lab in my 
daughter's middle school and while Garage Band, iVideo, etc. were big 
hits when a teacher was dedicated to running the lab, this year that 
teacher is doing a science classroom, so guess what the other teachers 
use the Mac lab for?  Web access and word processing.
The only real thing holding netbooks back is the same thing holding 
back our initial thin client rollout, that of supporting video w/o 
choppy playout.  But if the netbook has at least 250 MB RAM and can 
run the browser/decoder locally, that would solve that problem, and 
the far lower electricity requirements coupled with mobility and 
ability to run them as thin clients over a wireless network, that 
solves all the classroom wiring issues.  And if HiVision ever makes 
good its claim to offer $98 netbooks, then a netbook would be on the 
order of the cost of a plotting calculator.  For a classroom of say 30 
kids, $100 netbooks and a classroom LTSP server would cost about the 
same as some of those expensive interactive whiteboards, less if the 
parents supply the netbooks like they often currently do the plotting 
calculators.
Which is why I want wireless thin client use as well: that opens up 
all the use cases that interactive whiteboards using applications like 
TeacherTool and iTalc would allow.  Hence my vote for netbooks that 
can be used as wireless thin clients in addition to their normal 
standalone use at home.  Heck, even the Economist recommends Linux on 
netbooks now:
http://www.economist.com/science/tq/displaystory.cfm?story_id=12673233
Best, Daniel
Evan Leibovitch wrote:
Les R wrote:
Actually, Moodle is probably the killer app in this context, but 
really I am
talking about a need that only Open Source Software and Open 
Content can fill -
bringing affordable classes to kids.
    
Agreed.
  
I'm not so sure that this goal is best brought about by seeking to 
define a "killer app" anymore. The software world is so competitive 
and complex that it's hard to think that any single application would 
be compelling enough to make people change their operating systems 
and, indeed, their overall approach to computing.