Having been dealing with sending and receiving bitcoins on various services I have noticed a thing that always takes some extra time: checking that the address is right.
Since all transactions are irreversible and that every address looks the same, I have naturally been checking them many times before actually doing the transaction.
I have a way to simplify this: to develop a system of bitcoin-wide color coding checksums that are going to be displayed everywhere a bitcoin address can be entered (there is no way to force this of course, but if a system is good it is going to be adopted gradually).
The checksum should be color coded for fast comprehension by humans and also because it seems to be easier to remember. Making a checksum expressed as a letter, code or a similar symbol would pretty much be pointless, since it would be any easier to remember or faster to check than first/last letters of the bitcoin address itself.
I propose using 6 colors, red, green, blue, cyan, yellow, and magenta, since those are most distinguishable from each other, and involve just basic colors and mixing between them. To my understanding, people who have partial color blindness are unable to distinguish between one or several of those basic color, so using all of them increases chances that those people will still find this system usefull. They will perhaps not be able to tell difference between all 3 color bars, but perhaps the first one and last two, etc.
Keeping number of color small also makes it easier to adopt this system on many different sites with different designs. It is possible to make those colors dark, light, saturated, unsaturadet, etc, so that they will still be clearly distinguishable from each other and not stand out too much from the rest of any design.
Right now I have noticed that I have been checking the first and last letters of a bitcoin address to check that it is right (3-5 symbols). I am assuming many other people do this. To make this new system more compatible with that old behaviour, I propose that last 3 letters can be sometimes included in the color checksum, one letter per color. (Some websites right now also have this problem that the field is just too small and that you either see the beginning or the end of an address. If there was a color checksum that is always visible, I would not have to go into that field and scroll it just to check my addres, which is especially pain on mobile devices, with keyboard opening, etc...)
This way, for example if you are already instinctively checking last letters of a bitcoin address, you can still do this, but you will also notice the 3 colors on the websites that accept this. At the same time, on the website that does not support this, you are going to keep checking those last 3 letters, and won't really have to change your behavior. It's just that it will perhaps take you a little longer time to do the check, since recognizing letters takes more time than recognizing a color pattern. There can even be websites that don't want to display the least letters an extra time (they are visible in the end of the address, after all), and in that case you will still see the 3 colors after the address, so the system works without those last letters also.
How the checksum is actually calculated (how an address is "translated" into a 3-color code) should not depent just on the 3 letters, but on the whole address of course. That way there will be less collisions for the last letters+3 color code combination. (And it is that combination that the system will try to make each user to be familiar with).
So to reiterate, the point of this system is that each address is going to have it's own color combination, which is going to only depend on that address. That way, when you see your address in your wallet, you will see the 3 colors and (sometimes perhaps even unconsciously) connect those colors to that address. When you then enter your address somwhere on the internet, on a website that supports this color system, you will see the same 3 colors, and know that you have entered the right address. You won't have to check the letters like we all do right now. Even if you will still do that, you can at least very fast check if the address is indeed wrong, because it will display wrong colors and you will notice that instantly.
Another feature of this system is that we will have a standard way to display if a form field contains a valid address. Many times when I am copying an address to some field, I miss the last letter, or there can be some other mistake like a space inside an address, or some other symbol which have been copied errorneously. Right now I don't see any popular service having instant (before a form is submitted) display of whether an address is a correct bitcoin address or not. Using the color system, it will only display the colors for a valid address, and seing them will directly tell you that 1) you have copied the address correctly and 2) that this is the right one, since you recognize it's colors. (See the last example in my attached image for en example).
