I was looking at this because I want to make something similar. I've been looking for the software I want for the last ten years, and nothing comes close to the image in my head as to what software can do. So, I'll explain what I want.
I want something similar to this, which will replace email. It doesn't necessarily have to replace email, but it will accept emails and you can send emails out of it. The idea being that email will manage the projects. I'll explain. You create an email to people. You tag it as 'project' and it will create a new project, a distribution list, and automatically give the project a name (based on the subject). Any files emailed between you and others in that project via email will automatically be added to your project's workspace. Appointments set will be assigned to the project, and each appointment occurrence will have notes that you can keep for that occurrence. Tasks can be created for projects as well, and people can be assigned those tasks, and get email reminders.
With those features, if I don't recall what happened in the last meeting, or some client is asking about a file that I supposedly received, I don't have to go looking around trying to find which email on which day it was, as I'll have all project's emails together.
Once a project is finished, then emails between people in that project won't automatically be categorized, but there will be 'suggested' categories.
-- that said, this is nice, however, I can't figure out the ordering here, it appears there is none. Here's a simple test. Add 21 new notes. Just 1 enter enter 2 enter enter... it appears that the new notes are added to the left and that pushes everything else to the right, except when it comes to the extreme right and then it pushes that one all the way to the left and down one. That's an easy way to do it, but it's not easy to read. People are used to reading newspapers, Newspapers have a columnar format, and you read your columns. Classified ads are vertical columns as well, and if you are looking for something you look vertically within the categories. This on the other hand is horizontal categories, which is very confusing, especially since the category something is in is related to what's left of it, and how large that left thing is... in the example I give, you notice now 1,2,3 are from right to left on the bottom. Then 4 is slightly higher than those, on the very left. and then go right again, 5,6,7 all good, and 8 is once again higher... continue on until you get to sixteen, and now it all looks nice and tidy. Now edit 14 to say "14 this is a much longer note just as a test to see what happens with the columns". Now the whole thing looks like a mess.
tldr; use vertical columns to make the output predictable. People are used to spacial relation, so changing that because the content of one cell changes, makes the spatial relationship memory useless.