According to a Google presentation, the company is optimistic about unlimited storage capacities
Ever since Google released its highly acclaimed GMail service, many users have found interesting ways to make the most of the available space provided by Google. While other free email services battle over megabytes of free space, Google currently leads all other services by the gigabytes. Using 3rd party utilities, it is possible to map your GMail account as a psuedo-drive in Windows and use the account as a drag-and-drop file system. With these tools, some users have even sent themselves invites to chain together accounts for an effectively unlimited amount of network storage space.
According to reports however, sometime in the near future this activity may no longer be limited to 3rd party utilities. On Google's analyst day, a document presented contained information about a possible service called GDrive. The details in the presentation indicate that Google's long term goal is to provide a service to users that give unlimited amounts of storage space so that any type of file can be uploaded and stored. The presentation even indicates the service may be built to allow users access to their files from any device, and any location. The Google presentation, before it was editted and removed by Google, read (emphasis ours):
Theme 2: Store 100% of User Data
With infinite storage, we can house all user files, including: emails, web history, pictures, bookmarks, etc and make it accessible from anywhere (any device, any platform, etc). We already have efforts in this direction in terms of GDrive, GDS, Lighthouse, but all of them face bandwidth and storage constraints today.
Naturally, privacy concerns are rising with regards to Google's goals of collecting information. In the presentation, Google even indicates that it plans to collect "all" of the world's information, not just some of it. In this regard, it could be possible for Google to provide high-level services for government bodies that wish to collect information in a manner that would otherwise be too difficult without Google's search spiders.
No information on whether or not Google also plans to offer these types of storage services for fee-based subscriptions, though Garett Rogers from ZDNet hypothesizes:
In some screenshots of Gmail for domains, it appears there are different "account plans" that I assume provide additional email addresses. Could a similar system work for online storage? For example, 1GB free and pay $5 for each additional.