Differences between Keyhotee Mail part and BitMessage?

[HackFisher]

Keyhotee Mail has no Acks.
While a user is off line the length of time a message is stored is proportional to how much work was done while sending it, up to 1 month.
There is a fixed amount of storage and messages with more work can bump messages with less work.
We run servers that will cache all old messages while people are off line, Keyhotee will allow users to catch up without missing any messages.
All of this really only applies to a small subset of messages because eventually Keyhotee will directly connect to all of your contacts when sending them mail.  Broadcast will only be used for peer discovery or communicating with people not on your contact list.
Many services will spring up to host the mail for people depending upon the amount of privacy you require. 
All of this complexity will be hidden behind an interface that feels very much like normal email.

Thanks a lot, that does explain a lot of my questions.

[bytemaster]

Keyhotee Mail has no Acks.
While a user is off line the length of time a message is stored is proportional to how much work was done while sending it, up to 1 month.
There is a fixed amount of storage and messages with more work can bump messages with less work.
We run servers that will cache all old messages while people are off line, Keyhotee will allow users to catch up without missing any messages.
All of this really only applies to a small subset of messages because eventually Keyhotee will directly connect to all of your contacts when sending them mail.  Broadcast will only be used for peer discovery or communicating with people not on your contact list.
Many services will spring up to host the mail for people depending upon the amount of privacy you require. 
All of this complexity will be hidden behind an interface that feels very much like normal email.

[HackFisher]

I would like to study the differences between Keyhotee and BitMessage, especially about following parts, as I cannot understand how Keyhotee design them:

1. Message Transfer:
Quote from BM:

If the time in a message is too old, peers will not relay it. If the sender of a message did not
receive  an  acknowledgement  and  wishes to rebroadcast  his  message,  he  must  update the time  and
recompute the proof‐of‐work.

My question is that do Keyhotee have the same mechanism of old message? And do Keyhote hava ACK?

2. Scalability
BM:

If all nodes receive all messages, it is natural to be concerned about the system’s scalability. To address
this, we propose that after the number of messages being sent through the Bitmessage network reaches a
certain threshold, nodes begin to self‐segregate into large clusters or streams. Users would start out using
only stream 1. The stream number is encoded into each address. Streams are arranged in a hierarchy.

For Keyhotee, is it the same with BM that "all nodes receive all messages", how are those messages are stored on the network/nodes? or just not stored?

3. Behavior when the receiver is offline

We propose that nodes store all objects for two days  and then delete them. Nodes joining the network request a list of objects from their peer and
download the objects that they do not have. Thus they willreceive all messages bound forthem that were
broadcast during the last two days. If a node is offline for more than two days, the sending node will
notice that it never received an acknowledgement and rebroadcasts the message after an additional two
days. It will continue to rebroadcast the message, with exponential backoff, forever.

Any difference for Keyhotee?


References:

https://bitmessage.org/bitmessage.pdf