In the first article of this series, I talked about all the digital “stuff” that you have  today (photos, documents, music, browser bookmarks etc etc) that is spread over multiple devices (phone, iPad, iPod, personal notebook, work computer etc etc).

Products like Dropbox and ZumoDrive try to alleviate this problem by using a centralized storage location on the Internet (the Cloud).

ZumoDrive uses a file synchronization technology that is similar to a lot of backup solutions.

If you have folders or files that you know you need to access from different devices, you mark them for sharing with ZumoDrive. A copy of these folders/files is then uploaded to the ZumoDrive server. Changes made to the folders or files are synchronized with the online copies. Changes made to the online copies are synchronized back to the original copies.

When you are on a different computer, you can access these folders/files using a web browser pointed to zumodrive.com. Alternatively, if you have installed the ZumoDrive application, you can access these folders/files via a virtual drive (represented as a drive letter on Windows, or a disk icon on a Mac).

ZumoDrive also has apps for the iPhone/iPad, Android and other mobile devices.

Dropbox, on the other hand, uses a drop box approach (duh!). If you have folders or files that you need to access from different devices, you simply drag them to the Dropbox folder and voilà, the folders/files get uploaded to the Dropbox server. To access these folders/files from a different computer, you can use a web browser. Alternatively, if you have the Dropbox application installed, these folders/files are available from the Dropbox folder.

Dropbox, like ZumoDrive also has apps for the iPhone/iPad, Android and Blackberry (soon).

Both Dropbox and ZumoDrive focus on the most common types of files that users want to share between devices: music and photos. ZumoDrive, for example, integrates a music player and photo viewer into its Android application: you can play music directly from your music files on the ZumoDrive server.

There is little support for other kinds of file types. The assumption here is that if you have a Word document, for example, you already have an application that is capable on handling that on the device you are using. You will have to first download the document, then launch the associated application.

What is missing here is the functionality to deal with the case where you are in an Internet cafe and you want to access your documents or files on ZumoDrive or Dropbox.

ZumoDrive, in particular, has a security problem in such a use case: I discovered that it uses an on-disk cache to speed up repeat accesses. On my Android device, for example, the files that I access on ZumoDrive are stored on the SD card, in plain sight and unencrypted. On a computer, you want to be very careful if you are using it to access personal documents on a work computer. Copies of these documents are stored in the ZumoDrive cache folder.

To be fair, I have not used Dropbox sufficiently to determine if it has similar security issues.

Having said this, I think both ZumoDrive and Dropbox are very useful products. As we accumulate more content and acquire devices that are smart enough to handle all that content, there is a real need to be to have access from all those devices, without having to remember where everything is: it’s all in Dropbox on ZumoDrive!

However, both products only provide part of the solution. In the next article in this series, I will talk about non-music, non-photo files and the problem of access when you are on a public or friend’s computer.

Note: My friend Sarabjeet also mentioned the company called Box.Net as a competitor to Dropbox and Zumodrive. However, Box.Net is more geared towards the enterprise user. I see it as a SaaS version of Microsoft’s Sharepoint product.