It would require creating a new transaction, which might have to have its own fees, which might have to have its own change transactions, etc. The refunded amount would also be at risk of changing in a reorganize, which would invalidate all future transactions based on that one.

I see all comments are "pro" changes, so let me say "con".

Bitcoin was not designed for a big volume of small payments, neither in local data storage nor in network cloud.

All Satoshi's constants were considered very well.

Any changes should be deliberated quite deep.

Anybody could set up its own Bitcoin-backed micropayment service, it will not have all of BitCoin's advantages, but there could be a few players on this market.

--
mtve

I really like this idea, because it can be difficult for people to remember the exact meaning of all those prefixes: mili, micro, nano, centi, etc.

I'd propose another variant though, because of these reasons:
1. Having a number at the end of a unit can be confusing, especially if you have a list of values: 123 BTC3, 345 BTC3...
2. Pardon my ignorance but I never understood why there's a "T" in BTC  anyway
3. Most people associate bigger numbers with larger values.

B8C = BTC
B7C = 0.1 BTC
B6C = 0.01 BTC
...
B0C = 0.00000001 BTC

and if we are lucky:
BX1C = 0.000000001 BTC

+1 for standard metric prefix.

We only need a name for the smallest unit (10^-8 BTC), since unfortunately is not any of the 10^3 subdivision.  bitdust woudld be fine I guess.

Maybe you say that because you are american and most american are not familiar with the metric system, but I assure you that everywhere else in the world people know these prefixes.


Yes they are, at least for "kilo".  I'm pretty sure I've heard an american person talking about how he earned 50 'K', meaning 50 K$, ie 50,000$.

Also, with computers people are getting used to standard prefixes.  They talk about the speed of their processor in KHz, the size of their RAM in Go, the length of a transistor in nm, and so on...

I'm pretty sure they won't mind talking about mBTC, µBTC etc.

Moreover, if the period of variation of value for bitcoin is slow enough, then people will only talk about one our two units in their life time.  They will trade in mBTC for their daily expenses, and talk in BTC for their wage.  50 years later, their children might talk about µBTC or KBTC, who knows,  but the range of their expenses will probably not cover more than 3 or 4 prefixes, I guess.

Well actually, I'm Polish.
I know a lot of "normal" people, and most of them doesn't know said math prefixes.


Well, this is a valid point.
Still, i think my way is more intuitive.

Come on!  Everyone knows at least milli.  Perhaps with the exception of countries using some archaic units of measurement.  Millimetre and millilitre is common examples.  The exact meaning of micro and nano may be forgotten by people who are far past their primary education, but are by no means uncommon words.  Even my mother will know which is smaller, and I'll not be surprised if she knows their exact meaning either.

It certainly seems to make sense to have the next term (or even couple of terms or conceivably/dubiously next few terms) already out there right in front of them long before the time comes that they'll actually want/need to use them.

If they've been seeing millibitcoin day after day and maybe wondering what the heck it means and why is it even mentioned by the time an entire week or month goes by and bitcoins have increased in value yet another hundredfold, maybe by then they might have actually googled the word or something.

-MarkM- (Mind you I haven't actually checked that the first results for the term aren't porn sites or anything like that...)

Mega bump, but figured this was the best place to share my idea for naming small fractions of BTC.  It may seem complicated, but I think that with practice, this could be a manageable system for both online AND offline payments.  

Given that this is a global currency, and the metric system is used by the majority of the population, we should stick to a metric prefix system, similar to other ideas here in this thread.  I've added a few "rules" to help standardize and simplify the system.

Like so:

1 BTC = 1 Bit
0.1 BTC = 1 Decibit/Dec (Optional)
0.01 BTC = 1 Centibit/Cent
0.001 BTC = 1 Millibit/Mil
0.000,001 BTC = 1 Microbit/Micro
0.000,000,01 BTC = 1 Satoshi

In another form:

1 Bit = 10 Decs
1 Dec = 100 Cents
1 Cent = 100 Mils
1 Mil = 1,000 Micros
1 Micro = 100 Satoshi

Rules:  

1) The smallest unit possible is generally used.  Anything over 1 BTC is generally referred to in decimal (e.g. 1.35 BTC = "One point three five Bits")

2) Trailing zeroes should be used when interpretation of units is ambiguous. (See examples below)

3) Commas are used to the right of the decimal point every three spaces to assist unit assignment

4) Avoid awkward prices (e.g. 1.500,004,80 BTC).  Even so, could be read as "1.5 Bits and 480 Satoshi"

With this, you can easily speak lower prices without talking in decimals all the time. Generally, the fewer non-zero numbers in a BTC price, the better.

Examples:

0.40 BTC = 4 Decs OR 40 Cents
0.45 BTC = 45 Cents
0.452 BTC = 452 Mils
0.002,500 BTC = 2500 Micros OR 0.002,5 = "Two and a half Mils"
0.087 BTC = 87 Mils
0.000,346 BTC = 346 Micros
0.000,049 BTC = 49 Micros
0.000,000,12 = 12 Satoshi
0.000,003,12 BTC = 312 Satoshi

Thoughts, suggestions, criticisms? Having just 8 decimal places instead of 9 makes it slightly less intuitive than it could be when dealing with hundreds of Satoshi, but it's no different than saying that $1.32 is 132 cents.