The peanut gallery here seems a little uncritically critical ;)
The article didn't claim that fundamental ground had been broken in the theory of computation,, nor that the indexing scheme is completely novel. The point is that Zoe is packaged very nicely to use as a "personal web service".
1) it's portable (java)
2) it's free
3) it's open source
Sure, if I'm a fortune 500 company with a strong desire to burn money, I can buy Notes. But Zoe will run on my linux "personal server" (on my home lan accessible through cable modem) it requires no setup and it costs me nothing.
Which of these other solutions satisfy those criteria?