This is interesting, triple-entry accounting system. That is part of ConsenSys' vision. Not sure what they mean by "triple-entry". Double-entry relates to balancing debits and credits.
Ethereum is hard to explain. ConsenSys explains the four pillers of etherium here. Ethereum uses the same sort of technology as bitcoin, blockchain. Wikipedia provides this explanation of ethereum:
Ethereum is a cryptocurrency platform and Turing-complete programming framework intended to allow a network of peers to administer their own stateful user-created smart contracts in the absence of central authority.
Read this blog post and you will understand why "Turing-complete" is important.
InterPlanetary File System is basically a distributed file system. Watch the demo here.
XBRL, well, read this blog if you want more information. Clearly XBRL Global Ledger will be a part of the "XBRL" piece of the puzzle. What they don't mention is the US GAAP and IFRS Financial Reporting XBRL taxonomies. Other taxonomies will likely be important, such as other reporting schemes, tax basis information, etc. And, of course, when information goes into the digital triple-entry accounting system, you will want to get some of the information out in the form of a structured digital financial report, not old fashioned unstructured reports.
Here is another paper on triple-entry accounting.