By taking Megaupload offline and charging its leaders with criminal activity, the feds are hoping to drive purveyors of illegally distributed copyrighted content out of business. But in doing so, they've also eliminated a service that was used by many to share files acquired and distributed in a perfectly legal manner.

Megaupload is most well known for the distribution of pirated movies, games, software and the like, but a certain percentage of the site's usage—how much, we don't know—was legitimate. We reached out to readers today to find out how and why they used Megaupload to distribute and acquire content that didn't infringe anyone's copyright, and what they plan to do now that the site is off the Internet.

There is no shortage of file-sharing services, of course. Why would someone who's not a pirate use Megaupload instead of, say, Dropbox, which presumably is under no threat of closure? Readers and followers on social networks tell us that generous storage allotments, ease of use in sharing, and fast upload speeds were among the key reasons.

While we expect the vast majority of users would have their content backed up locally, there is no readily apparent way for Megaupload users to regain files they've hosted on the service. Refunds for holders of premium accounts is another unresolved issue. We've asked a Justice Department spokesperson if any method of re-downloading legitimate content from the servers will be available, or if the content will still be on the site should Megaupload ever be allowed back online.

In response, a Justice spokesperson cited the site's FAQ which covered the possibility that their files might one day be lost or inaccessible: "This is still an ongoing matter," the spokesperson told Ars. "It is important to note that Megaupload clearly warned users to keep copies of any files they uploaded. Megaupload.com expressly informed users through its Frequently Asked Questions ('FAQs') and its Terms of Service that users have no proprietary interest in any of the files on Megaupload’s servers, they assume the full risk of complete loss or unavailability of their data, and that Megaupload can terminate site operations without prior notice."

Easy to share

"We do a decent amount of video stuff here and so I have to move too-big-for-email files around with some regularity," staff attorney Michael Weinberg of Public Knowledge tells Ars in an e-mail. "I like sites like Megaupload because they do not require an account—you just upload it, get the link, and send it out. It is also easy to tell other people to use it because you do not need to make a new account."

Public Knowledge is a prominent SOPA opponent, and Weinberg was using Megaupload throughout the SOPA debate and right up until yesterday's action against Megaupload. "As luck would have it, over the weekend I used my home laptop to pull down the stream of the House Judiciary Committee SOPA markup," Weinberg says. "I wanted to transfer it here to work so that I could cut it up into a video we were using. I uploaded it, but before I had a chance to download it Megaupload was shut down. I can't speak for everything happening on the site, but Megaupoad was providing me a completely legitimate service for a completely legitimate end."

Reader Mark Ellul tells us "I used my account for online storage and backups, also to send my personal home video files from Spain to Australia, so my parents can see HD videos of their granddaughters. I have received tweets from DJs who used it to share their legal creations. Obviously there was a pirated use, but there were so many uses to have unlimited space in the Web. Now I find it hard to trust in any service, because Dropbox or any of the other competitors could be brought down by the FBI."

The free Megaupload service allowed uploads of files up to 2GB in size and total storage of 200GB. Fee-based plans offered unlimited storage.

One user in Colorado who goes by "daveIT" in the Ars forums said he paid for the premium service for increased speed, and used it to collaborate with a friend in Alaska on music tracks. "Not a huge blow personally—other than having to waste the time to re-upload tracks on my slow DSL," he wrote, noting that with Megaupload he had uploaded files 6GB to 8GB in size with no problems.

Perhaps worst of all, the reader may be out of luck in getting a refund. "I had just renewed my subscription for 2 months and this happens a couple days later...wondering if they will refund that??" he wrote. "They'll probably need it for litigation!"

Megaupload important for Android developers

Another reader tells us in the forums that "I'm an Android phone enthusiast, and Megaupload was one of the best ways to distribute custom ROMs and other Android mods. In fact, the ROM my phone is running right now I downloaded from MegaUpload shortly before it was shut down. There are a number of similar sites for this use, but Megaupload was always the fastest."

On Google+, Massimiliano Fanciulli tells Ars "I've used Megaupload for distributing betas of my app Sleepy before publishing it on the Android Market. It was quick and easy to upload and share things."

Fanciulli said he might start using Google Docs to share files instead. Other users suggested RapidShare, FileSonic, Dropbox, or even Amazon's Simple Storage Service (although Amazon's developer-focused service is for more technically inclined users).

Professional musician Suzanne Barbieri e-mailed us to note that she used Megaupload to store and share music in part because most of her projects "are too large for something like YouSendIt. A Megaupload free account allows you to send files of up to 2GB. I have no idea where I will upload files now." Barbieri tells Ars the pre-release tracks she makes are confidential and intended only for the recipients' use, so she doesn't like the files being in the US government's hands.

"I do session work in my home studio and upload the files so the clients can download them," Barbieri says. "The work I do for them is usually urgent with tight deadlines, so I have to be able to upload files. A courier service would be too expensive and too slow. I also use Megaupload to get my own music to my record label."

One reader admits to having used Megaupload "for both legal and iffy purposes," including distribution of modified Minecraft clients to friends, and for obtaining rare albums and games. "Any time you needed to send a couple of large files to someone, it was easy to just zip them and dump them onto Megaupload or another such site," he says. "Another added bonus was anonymity."

Another reader tells us of accessing Phish concert MP3s—which are distributed legally because the band permits recording. Rob Beschizza, managing editor of Boing Boing, notes that public relations people use Megaupload to send the site "everything from high-resolution images to unreleased albums, videos and such for us to review and publish."

Vancouver resident Geoff Luk says he volunteered to take photos and videos at the 2010 Winter Olympics and used Megaupload to store files that were 4GB in size. "The biggest loss of my media is two ISO DVD images that I created from PPT slideshows and photos and video taken while I was volunteering with the 2010 Vancouver Winter Olympic Games," he says. "As the team I worked on was huge (about 75 Downtown Vancouver, and another 25 in Whistler/Blackcomb), it was nigh impossible to physically share both DVD copies of the photos, videos, and ISO files after the Olympics had ended."

Luk says he has everything backed up locally, although uploading files again to another service will be inconvenient.

Users say federal action "too broad a brush"

One Ars reader suggests in the forums that users who lost access to content and paid for services they now won't receive should file a class-action suit against the US government. "I am not saying that distribution of illegal content is ok, but killing all other legitimate content as a sort of a ' collateral damage' in this case is surely not ok," the commenter writes.

While such a suit seems unlikely to succeed, the sentiment is reflective of users' anger about the lost service. A book editor named Cassandra Olivia says graphics designers and editors she works with use Megaupload to exchange files for review, and that she uses it herself for sharing family and vacation photos with relatives who are "just technologically adept enough to click on a link."

"I'm glad my Megaupload account was just backup and I still have the photos somewhere, but now I have to retrain my family into using Dropbox or similar," she says. "Taking Megaupload down without distinguishing between infringing and non-infringing content did the legitimate users a disservice and was a violation of due process. Too broad a brush, I think. I hope I get my account, and my photos back."

How many other Ars readers used Megaupload? Which alternative services will you use now? Feel free to weigh in.