wow. you use OP_RETURN for this.. even bitcoin core developers are against this kind of usage since you bloat the chain.
Please go ahead and take a look at the documentation
http://atomicdac.org/?page_id=11033 We are making use of the OP_RETURN segment of transaction scripts in order to store a very small amount of information (about 70 bytes right now, although we have raised the limit for testing to 200 bytes to allow us to expand in the future).
most Bitcoin transactions are around 250 bytes in size, depending on the amount of inputs in the transaction script. Therefore an ATOMIC transaction, in the worst possible scenario (large number of inputs for example) the script generated could end up being around 300 bytes in size.
If you take the 70 bytes, which as I said is more than we actually use) and multiply that by 80,000 which is a few thousand more Bitcoin transactions than there have been today, the total amount of data would be 5 megabytes per day.
http://www.matisse.net/bitcalc/?input_amount=5600000&input_units=bytes¬ation=legacyHaving 80,000 transactions a day would be great, and anyone who can't handle 5 MB a day (once we get to that huge amount of transactions which has taken years for Bitcoin) is free to use the light version of the software
please feel free to send me an email any time with your questions or criticisms!