Megaupload and Megavideo were instantly shut down by federal prosecutors last Thursday, after the site's executives were charged with mass copyright infringement. But not all of the site's 50 million daily users were breaking the law.

There were legitimate uses of Megaupload. Many people use file-sharing sites as 'clouds,' places to store legitimate files, which they can access anywhere in the world, Web commentator Russell Brown told TV One's Breakfast this Morning.

Brown explained that it was difficult for file-sharing sites to monitor those who were violating copyright laws, and the accessing of different files at any one given time. The eventual case will turn quite greatly on how much the Megaupload founders knew, Brown said.

Four company executives, including Megaupload's founder Kim Dotcom Schmitz, were arrested after the indictment was delivered by the Department of Justice on Thursday. Each individual has been accused of having involvement with copyright infringement and a conspiracy to commit money laundering.

The FBI spent close to two years collecting evidence that shows the executives knew the types of infringement that were taking place on their site. U.S. authorities believe Schmitz masterminded a scheme that made more than $175 million by copying music and videos, according to Reuters.

Schmitz has denied charges of Internet piracy and money laundering, telling a New Zealand judge on Monday that authorities were trying to paint the blackest picture of him. Megaupload's lawyer told the judge that the company simply offered online storage.

The judge did not deliver an immediate ruling for Schmitz's bail application. Given the breadth of issues covered in this bail application and the seriousness of the issues, I am going to reserve my decision, he said.

Federal agents argue that Schmitz's online companies have cost the film and music industry hundreds of millions of dollars. Authorities want to extradite the New Zealand citizen based on these charges.

Those who try to access Megaupload's Web site now are greeted with the following message:

This domain name associated with the website Megaupload.com has been seized pursuant to an order issued by a U.S. District Court. A federal grand jury has indicted several individuals and entities allegedly involved in the operation of Megaupload.com and related Websites charging them with the following federal crimes: Conspiracy to commit racketeering, conspiracy to commit copyright infringement, conspiracy to commit money laundering, and criminal copyright infringement.

The impact of the site's shutdown has sent shockwaves into the online world. Other file-sharing sites, such as FileSonic, have now shut down all sharing functions of their sites.

Our service can only be used to upload and retrieve files that you have uploaded personally, a notice on their Website says.

Here are some alternatives to Megaupload and Megavideo that are still online:

Mediafire: A simple file-sharing interface that allows you to drag-and-drop files, 200 MB at a time. Need to drag bigger files? Just sign up for a MediaFire Pro account ($9/mo.). Files can be stored for as long as you want, with unlimited storage space.

Dropbox: The service is a little more limiting. You can't drag-and-drop unlimited files indefinitely, but you can drop and share music, videos and photos in a public folder.

Rapidshare: This is probably the site most similar to Megaupload. It allows you to upload large files seamlessly and send links to other users. You can sign up for a free account and upload files as large as you wish. The files do, however, expire. For unlimited usage, you will need to sign up for a membership ($13/mo. to $130/yr.)

YouSendIt: This started as an e-mail alternative to help people send files to one another without clogging up inboxes. Now, like Dropbox, it's a popular interface to share large video files with friends, although there is a 50MB upload limit and only 2GB of storage per person. Members can get larger upload and storage limits for $10 per month.

Minus: This started as an image-sharing site but quickly evolved into a file-sharing service. Users can drag and drop files and create links to send to friends. A free account includes 50 GB of storage, and files up to 2 GB can be uploaded. There is no time restriction for the files and sharing is made easier with an easy-to-use mobile app that comes as part of the service.

Must Read: Kim Dotcom: What's Next For Megaupload, Megavideo Founder Denied Bail?

MUST READ - iPad 3 Features: What to Expect and Not to Expect (Rumors Roundup)

MUST READ - iOS 5 Untethered Jailbreak Absinthe: Should You Jailbreak Your A5 Device?

MUST READ - MacWorld-iWorld Expo 2012: Top 10 Must-Have Gadgets, Software and Apps (PHOTOS)