The Wii has a storage problem. With only 512 MB of on board capacity, if you're at all interested in downloading games or Wii Ware, well you'll quickly run out of space.
According to various sources, including Spong, Nintendo are definitely aware of this problem, but aren't working on a hardware solution.
So, what's left? Online storage. Just like logging into your gmail or yahoo account to check your email, your games could all be sitting there, waiting for you to enjoy.
We'll see if there is any news on this any time soon.