After watching some of one of the 28c3 talks, It got me thinking about just how scalable Bitcoin really is.
With the size of the blockchain currently, given the number of transactions/users, will the size of the blockchain be manageable as Bitcoin adoption increases?
As an example (no answers about "this will never happen" please), if Bitcoin was as large as a company like VISA, hundreds/thousands of megabytes would have to be transmitted over the network daily and stored in the blockchain. This is not including other things being stored in the blockchain that essentially shouldn't be (Eligius putting prayers in the blockchain for example).
This would mean that most casual users would need to use a thin client as storing the blockchain and keeping it up to date would require super fast internet and masses of hard drive space. (imagine Visa's 92 billion transactions per year)
Are there any studies into the scalability of the blockchain? Or is the assumption that technology will be so advanced by the time of this ever occurring that it will not be an issue? (which doesn't sound like the greatest conclusion in my opinion)
Also, quoting the wiki:
At very high transaction rates each block can be over a gigabyte in size. These blocks must be stored somewhere. Whilst for speed it'd be ideal to store the block chain entirely in RAM, for cheapness storing only the hot parts in RAM and the rest on disk is the way to go. A 3 terabyte hard disk costs less than $200 today and will be cheaper still in future, so you'd need one such disk for every 21 days of operation (at 1gb per block).
3 TB every 21 days? 52 TB a year for the blockchain alone? Is that REALLY scalable?