The problem is good described in the following quote:

Another problem is that with so many small transactions, the bitcoin block chain could, at some point, become unmanageable in size. Ortutay, the CoinWall proprietor, said:

“You don’t want to send a lot of tiny transactions over the network that will bloat the block chain – make it really big. That’s a problem. I think that’s a valid argument.”

Coinbase actually uses off the block transactions to process its daily bitcoin transmittals. The company then allocates them on the blockchain as much larger grouped transactions at a later point in time.

Ankur Nandwani, who runs the open-source micropayment system BitMonet, believes that developers are already working on solutions if the bitcoin blockchain does inflate to an unmanageable size. One of the ideas is called a ‘micropayments channel’, a concept that has been circulating for a long time.

“The bitcoinj library has added support for micropayments channels, which when implemented by different players in the bitcoin ecosystem, will do a lot to ease out the fears of microtransactions filling up the blockchain,” Nandwani said.

Full article

Also there are a lot of other good ideas…

What do I think: what about to have a bitcoin wallet with built in an altcoin for a change or something like that.. But anyway it must be easily changed to bitcoins, the same easy like to send bitcoins. What about decentralised exchange inside the wallet? Is it already done somewhere? I’m going to think more about this. If it is possible may be you will see the news about such a wallet here on my blog