A deep dive into Dropbox, SkyDrive, and Google Drive

Dropbox has a visual style all its own, but it works. This file and folder listing is the opposite of cluttered, and once you learn what the icons along the top do, you're pretty much home free.

See that Get free space! link at the top of the page? Dropbox does a lot of upselling, and they're sometimes a little pushy about encouraging you to invite your friends in exchange for extra gigabytes.

As part of its installation, the Dropbox Windows utility adds a shortcut in the Favorites pane that points to your local Dropbox folder. Green checkmarks on each file and folder mean that they're in sync with the files in the matching Dropbox web folders.

Pop-up alerts appear in the taskbar when files are added, deleted or changed. You can also get notifications via an RSS feed.

This log file lists every addition, deletion, and change to your Dropbox storage since the opening of the account.

Clicking on the link for a deleted file or folder lets you recover it from the trash. You can also view a file's Previous Versions and undo changes that were made in a recent edit and save.

Deleted files and past revisions are saved for 30 days. You can extend this backup by upgrading to a Dropbox Pro account and purchasing the Pack-Rat add-on.

Every computer that's currently connected to your Dropbox account and syncing changes is listed on the administrative screen.

You can add a computer here (although it's generally easier to do so from the client side). You can also change the name of a computer to make it more descriptive.

That Unlink option ends the synchronization relationship between the client software on that computer and the Dropbox web folder. It doesn't delete the files from that computer, only prevents further updates from being made.

Dropbox deserves its reputation for ease of use. That usability is the direct result of this clean, uncluttered design.

The option to copy a link, to an entire gallery or to an individual photo, is new.

This gallery view lets you scroll through all the photos in a folder (galleries are only created if they're in a subfolder of the Dropbox Photos folder. You get a different view (and the ability to get a link) if you click to open a photo file directly from the file listings. That view doesn't include the row of navigation thumbnails shown here.

Dropbox is pushing its photo features hard, offering free, automatic storage upgrades if you upgrade lots of photos.

If you share a folder with another person, its contents sync to their computers, and they have full read-right access to everything in that folder. You can use email to invite another person (they have to have a Dropbox account), or you can pick from a list of Facebook friends.

To grant read-only access to files and folders, use the "Get a link" options. Anyone who accesses the files using that link can make a copy, but can't change the contents of the original file or folder.

SkyDrive's file and folder listings are much more dense with information than their Dropbox counterparts. You can filter the list, showing only photos or documents, for example, using links in the left pane.

The information under the Shared With heading makes it easy to see whether a folder is public, shared with some people, or completely private. Those four small icons above the Files list--Word, Excel, PowerPoint, and OneNote--offer a hint of what's supported in the Office Web Apps.

Microsoft released the long-awaited utility that connects Windows Explorer to a SkyDrive account so that files can automatically be synced. Like Dropbox, SkyDrive lets you choose where to create your local folder for sync purposes. It then adds a shortcut in the navuigation pane.

The green checkmark overlay shows synced files, which otherwise look and act exactly as if they were stored only locally.

Like its competition, SkyDrive syncs the contents of a single folder and its subfolders. But unlike either Dropbox or Google Drive, SkyDrive allows you to browse the file system of a connected PC. If your remote PC is on and this option is enabled, you can browse its file system and retrieve files you left behind, even if they're stored outside your synced folder.

This "Fetch" option is enabled by default. You can disable it during setup, or afterwards by right-clicking the SkyDrive icon in the taskbar, opening the Settings dialog box, and clear =ing the "Fetch files" option.

When you browse the contents of a folder filled with photos, the resulting gallery is visually arresting. A pane along the right lets you add or edit details. It also shows current sharing options.

Note that you can adjust the permissions for folders with muchmore granularity than you can in Dropbox. You can set up shared folders so that some users can view files but not edit them or add new ones. In a feature that's been part of SkyDrive for a long time, you can click to get a link and share a file or folder even with someone who isn't signed in with a Windows Live account.

Even in slide show view, the information pane on the side is visible (although you can hide it with a click). As the Information pane makes clear, these photos are full-sized, high-resolution files.

From SkyDrive, you can share files via email, by creating a link, or by using existing social media connections from Facebook, Twitter, LinkedIn, or other services.

By default, shares are read-only. Click the "Recipients can edit" box to allow full sharing.

The four Office Web Apps work in non-Microsoft browsers, with support for in-browser editing in Chrome (shown here) and Firefox.

Not all editing features are available in the web apps, but you can make changes without affecting those missing formatting options.

You can also share documents directly from the editing screen, using the File menu shown here.

The ability to create, share, and fill OneNote notebooks in SkyDrive is unique among these three apps. These notebooks are useful for sharing information about projects and about vacation plans, as shown here.

There's no doubt that this is a Google service. If the interface shown here looks familiar, that's because it used to be called Google Docs. Although you can store other types of files here using the Windows Explorer interface, I was unsuccessful in uploading anything other than

With the Google Drive Windows utility installed, files sync from Google Drive storage to a local folder. Slim green checkmarks indicate synced folders.

The large icons indicate Google-formatted docs, which are only available for editing if you are online or if you are using the Chrome-only Offline features.

As befits the maker of Gmail, sharing from Google Drive is exclusively via email. (You can choose from your Gmail contacts list or enter addresses directly, or both.)

Google Drive sharing permissions offer far more than Dropbox. You can make a folder public or private. For each person you share a file or folder with, you can give them the rights to edit, view and comment, or simply view. There's no "get a link" feature.

Google's apps are strictly browser-based; if you want offline editing, you need to use Chrome and make some configuration changes.

Docs don't offer the same full range of features as Microsoft Office programs and work best in an all-Google environment. Importing and exporting files to Office formats can result in missing or damaged formatting.

For collaborative projects having access to previous versions lets you roll back unwanted edits quickly.

Neither Dropbox nor SkyDrive can boast this unique feature of Google Docs. When you create a form, you can define fill-in-the-blanks fields, checkboxes, and options, and then publish the result as a survey, using a link or email.

When you open a form you sent out for others to fill in, you see the data in a spreadsheet, ready for tabulating or charting.

It's a very handy feature, and one you can't do with the other alternatives.