When comparing Dropbox vs Skype, the Slant community recommends Dropbox for most people. In the question“What are the best file sharing services?” Dropbox is ranked 9th while Skype is ranked 27th. The most important reason people chose Dropbox is:
You can use Dropbox via website, by installing a desktop client that creates a folder that you simply drag and drop files into, or with their mobile app. Everything synchronizes across all devices used and cloud storage. And Dropbox offers easy methods of sharing whatever is within it.
Specs
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Pros
Pro Easy to use
You can use Dropbox via website, by installing a desktop client that creates a folder that you simply drag and drop files into, or with their mobile app. Everything synchronizes across all devices used and cloud storage. And Dropbox offers easy methods of sharing whatever is within it.
Pro Cross-platform desktop and mobile
Dropbox is available on iOS, Android, BlackBerry, Windows, OS X and Linux. By having a client for so many OS's pretty much anyone is covered no matter what kind of device or OS they are using.
Pro Allows sharing a folder
Using a desktop client: right click on the folder you want to share and select Dropbox > Share This Folder, then enter the e-mail addressees of people you want to share the folder with.
Pro Smart updates to big files
If a small portion of the file is changed it sends/receives only the differences (not the whole file), which is fast and bandwidth-efficient.
Pro Allows sharing a single file via link
Whether using desktop client or web interface, simply right click on the file you want to share and select Dropbox > Share link, then send the link to the people you want to share the file with. The recipient does not require a Dropbox account.
Pro Up to 18GB of free storage space
Dropbox personal accounts start out free, with 2GB of space, but users can get extra space by recommending the site to friends, or taking part in events like "Dropquest", where users can win extra space by solving puzzles.

Pro Linux support
Dropbox offers native Linux support, integrates with Nautilus file manager.
Pro Reliable
Pro Desktop client has no file size limit
As long as you have enough storage available, you can upload files of any size using Dropbox desktop client.
Pro Folders can be downloaded compressed to save bandwidth
To save bandwidth and download speed you can choose to compress a folder into a zip archive for download.
Pro Adjustable bandwidth use
To not slow down the network or save traffic you can limit the upload and download speeds of Dropbox.
Pro Lots of addons and integrations
There are official and third-party Dropbox add-ons that extend the functionality of the service and add ease of use of existing features.
Additionally, Dropbox can be integrated with existing applications to bring its functionality to other apps.
Pro 30-day version control
Dropbox keeps deleted and earlier versions of files for a month.
Pro Instant disaster recovery
Your files always synced online means instant disaster recovery. When your hard drive becomes unbootable, pick up another laptop and just carry on with your life from where you last saved.
Pro Available free storage can be increased with referrals
You get extra free space for you and your friend if they sign up.
Pro Fast sync speed
Pro Easily connect with others due to how popular the service is
There's a good chance that whoever you're trying to reach has Skype already set up and familiar with it, avoiding the hassle of installing and getting to know new software.
Pro Screen sharing
You can show your whole desktop, a select part of the screen or a specific window over Skype.
Pro Cross-platform
There's software for Windows, Mac & Linux and apps are available on iPhone, Android, and Windows Phone.
Pro Group video for free
You can hold video calls with up to 10 people.
Pro Available on Linux
A stripped down, minimalist version of Skype is available for Linux.
Pro File sharing
Skype allows you to send any files (MP3s, images, text, etc.) by simply dragging and dropping then in the chat window making it simple to share things with colleagues.
Pro Cheap fixed phone number
Starting at $5/mo you can get a Skype number.
Pro Send SMS and make regular calls
With Skype Credit bought or a subscription, you can send SMS and make direct calls.
Pro Group chat with archive / records
Pro Powerful 1:1 chat and also group chat
Cons
Con Too little free space
There is just too little of free space available comparing to the competition.

Con Not secure
They don't apply end-to-end encryption, files are visible to admins, governments, etc..
Con No privacy
Extensive collecting and distribution of user data to commercial third parties.
Con Consumes a lot of CPU resources when syncing many files
Con All-or-nothing (non-selective) upload
Uploading generated contents (cache, compiled code, etc.) is prone to conflicts, wastes bandwidth and free space.
Con Low bandwidth
Con Dropbox keeps deleting features, chasing customers away
For instance, all photo albums got deleted. It used to be very easy to share a couple og photos, now it's PAINFUL and must be done file by file.
Con Nocive development model
Takes a lot of decisions that usually damage community, from deleting features to making impossible to use with other filesystems than ext4 because they decided without a plausible reason (they said it was about xattrs, but all modern linux filesystems supports xattrs, so it's bs.)(they remove this later, but it's too late).
Con Problems when synching between Linux and Windows devices (unconfirmed)
This summer I lost thousands of files due to this problem on older projects which subsequently needed revising and had to be rebuilt as tons of the source was gone.
Con Restricted only to 3 devices for FREE accounts
Recently dropbox decreased the number of linked devices to 3, so you can't have more than 3 linked devices. This is problematic if you use Dropbox to sync between your computers.
Con Can unintentionally delete your files if you reinstall your OS without closing Dropbox
If you reinstall the operation system for your PC and you do not close Dropbox, it will delete all files.
Con Plagued by bugs on all platforms
Crashes and other bugs are prevalent on Android, Windows and other platforms.
Con Subpar video quality with more than 5 users
Skype has significant problems with multiple users and video quality. Skype recommends that a max of 5 users group chat as video quality is severely affected. Even webcams tested with other chat services showed lower quality when used with Skype.
Con Not a feasible alternative as a professional team chat
Missing key feature such as centralized mgmt, centralized billing, data retention policies, ...
Con Poor quality when screensharing
It is not possible to manually set resolution or bitrate, and Skype often defaults to a resolution so low that text is unreadable. It is also not possible to transfer control over mouse and keyboard.
Con Slow filesharing speed

Con Owned by Microsoft
Con Obnoxiously large ads
Ads take up over 25% of the usable space.
Con Poor Linux support
The version available for linux users is quite outdated, and does not support some of the newer functionality, such as the free group video calling and screen sharing.
Con Requires both ends to be online (if neither end is using a cloud-enabled device)
Messages are sent and received only when both ends are online, if neither end is using a cloud-enabled device. In this case, if you are online 9-17 and your recipient is online 18-3, messages will never be delivered.
Con MIcrosoft (Skype's owner) actively assists eavesdroppers
On the other hand, if you lose your copy of one of your conversations, you may be able to get a copy of it from your government with a little bit of luck and a public records request.
