Ah thank you for these questions! I've been in my own little world as far as my side-chains go for quite some time so I haven't been able to articulate the need for several of these pieces. IPFS is a p2p file system that stores it's contents by the hash of its contents and not the name of the file. Why this is necessary(and has very little to do with the VR explorer) is thus: For collaboration to happen each party needs to agree on what the other parties know and intend on doing. For instance ACTs are non-transferable therefore if funds were sent to the multi-sig account it's possible several of the people running similar software would try to create these accounts and the cooperative nature would be lost. So what is stored in IPFS is a list of information such as who is selling ACTs and for what price. Who is in the queue to create accounts. What the price for accounts and delegation for 30 days is. What the ref block and expiration time for multisig operations are. etc. This information determines the state that needs to be agreed upon. Using IPFS a matching hash not only is proof that you agree upon a state, its also the address of the state so anybody can join the network and start participating in it with out having to replay from genesis. The state stored in IPFS is the consequence solely of information that exists in the streamable blocks. Other information like how many ACTs or SP an account has comes from the Steem API, what time it is is generated locally... these are polled from participants and also published with the custom jsons to make it in to the state file. After about 24 hours the information that was stored in IPFS gets garbage collected and the cooperative doesn't need to worry about older information(which can be found simply by replaying from genesis).

This is how the group shares and verifies information... including who is responsible for broadcasting operations like delegation/undelegtion/account creation. This paradigm will work to alleviate the need for any thirdparty trust in situations such as insurance, banking, brokers and betting.