Facebook has built up a formidable store of data on its five hundred million users, including billions of status updates, comments, photos and videos. Now the company is setting that data free, by allowing users to download a file that contains all of the information they've uploaded to the site. This change shows that the company is responding to the complaints of advocates concerned about how Facebook handles the data it collects. But it could also make easier for a new social network to get started.

This change was one of several announcements made yesterday to address common complaints about Facebook. Privacy advocates have criticized Facebook for making it difficult for users to retrieve their data, for how the company shares data with third parties, and for making it difficult for users to close an account. The company has also come under fire for making changes without fully educating users about what those changes mean, and for lacking ways for users to control who sees the information they post.

Facebook also announced changes to the way groups work on the site, which should make it easier for users to post information intended for certain people. When a user posts information and wants to restrict it to a group, Facebook's algorithms will guess at who should be in the group--partly drawn from groups that have been created by others--but the user has control over who to select. Facebook also launched a dashboard that lets users see what information third-party applications are using, and when those applications last requested data.

Letting users download all their data could be the most important change, and it could have unintended consequences. A new social network--such as a the one Google is rumored to be building--could use that data, with users' permission, to automatically add information to new users' profiles.

It may seem strange for Facebook to open up one of its most valuable resources this way, but the company is obviously working hard to repair its image. And other companies already offer similar services, for example Google's Data Liberation Front.

Twitter is changing its site to make it easier to use and navigate, and to give more context to posts that people see on its website. The changes will add a variety of informative panels to supplement the rapid exchange of information that's always taking place on the site.

For example, Twitter users often post links to pictures and videos. The new site will pull those onto the page so that people don't have to leave to view that content. Twitter has accomplished this in part through partnerships with companies that provide these services.

The new site will also provide contextual information for tweets, giving users related posts, for example. It will also make it easier to see profile information about who has posted a tweet without navigating away from the page.

Though the individual changes may seem small, together they suggest a focus on the aesthetics of the site that Twitter historically hasn't had time for. The site has spent most of its life trying to keep its head above water and prevent crashes from being too frequent.

The changes also seem likely to make people spend more time on the Twitter home page, rather than navigating away from it constantly. This could affect the group of applications that have grown up to supplement Twitter, in some cases undermining their functionality. It's also possible that the changes will make advertisements on Twitter more valuable. They could be coupled more closely to other content, and there might be more opportunities to present them.

A small group of users already has the new Twitter, and the company expects to add everyone in slowly over the next few weeks.

Science purists might find much to complain about in the newest installment of the Iron Man franchise, starring Robert Downey Jr. Admittedly, Tony Stark "creates an element," and heroes and villains alike seem able to break into high-level computer systems with little more than the wave of an iPhone look-a-like. But I expect computer scientists and designers will be impressed by the movie's natural user interfaces.

There's a long tradition of the interfaces envisioned in movies becoming research projects in real life. For years, techies have chased the "Minority Report interface" inspired by a scene in the Tom Cruise action flick in which the main character does his police work by donning a pair of gloves and diving into a hands-on manipulation of his data. Johnny Lee, a researcher in Microsoft's hardware division, gained acclaim for hacking together a version of the interface using a Nintendo Wii. The company Oblong has been working for years on the g-speak interface, a slicker implementation of the same concept.

Earlier this year at South By Southwest Interactive, a computing and design conference in Austin, Texas, I noticed that Iron Man had stolen the designers' hearts. I attended multiple panels where designers showed clips from the first film and described what it would take to make that vision a reality.

Iron Man 2 had several enticing scenes of the main character interacting with his computer. Leaving aside the computer's improbable level of intelligence, Stark interacts with it through sophisticated voice recognition. This is a feature taken for granted in almost all science fiction films. More intriguing are the suggestions for gestural interfaces.

When Stark is mid-design and doesn't like what he's working on, he grabs it off the projection and throws it into the trash. This allows him to throw away a virtual idea with as much expression as can be used with an idea that's taken physical form. At one point, he performs a 3-D scan of a physical model because he wants to create a version that he can manipulate easily. He lifts a projected image off the physical object and becomes able to spin it, change its size, and alter it with flicks of the hand.

What makes the interface look most attractive is how physically involved Stark becomes in design. With the power of voice and gesture combined, Stark is able to give small, quiet commands when contemplative, and become more expansive and hands-on when excited. The vision of a computing device that's able to adapt so smoothly to the user's mood and circumstance is compelling to say the least.

Stark's natural interface also displays a problem that designers still have to overcome with this type of design. Watching closely, it's clear that it's ambitious to call such an interface "natural." Stark knows an entire vocabulary of gestures that would not be obvious to someone approaching the interface for the first time. For natural user interfaces to take off in the real world, designers will have to convince users that learning this new method of interaction provides value that can't be had with keyboard and mouse.