application updates

So...what change is it that you think ought to be made?

Once you are able to state that, you can post at http://brainstorm.ubuntu.com, and developers will see and consider your idea. But it is important that you are clear about exactly what you think should change (and be able to state it clearly), before you post there.

Many users ask why the very newest versions of their applications are usually not provided as updates. The reason for this is that spontaneous breakage of formerly working programs in Ubuntu, both in the sense of introducing new bugs and in the sense of pulling out one user experience from under users and replacing it with another, is considered a bad thing. Therefore, it is necessary that Ubuntu's default behavior be that updates fix only security bugs and other serious bugs that severely impact stability or usability. See https://wiki.ubuntu.com/StableReleaseUpdates for details.

Most users for most applications find that this works well, but many users do want more cutting-edge software some of the time. There are a few ways to get it. If a newer version of some software is provided in a *later* release of Ubuntu, it can sometimes be obtained in an older release (so long as that release is still itself supported) using the -backports repository for that older release. See https://help.ubuntu.com/community/UbuntuBackports for an explanation of this. That page also helps to further explain Ubuntu's policy regarding updates.

But in addition to not providing updated versions of all software in Ubuntu, -backports still just gives you the latest version currently available in *some* stable Ubuntu release, which may not be the latest version of the software. So to get the latest version of the software, you can use a PPA. Most popular software widely used in Ubuntu has a PPA (or more than one, for different options) which you can use to keep up to date with the very latest version (either the latest stable version, or the latest experimental version which will crash a lot but give you the very most bleeding edge features--you should only use a testing version if you're willing to tolerate this, and want to submit bug reports to help improve the software).

Often there are official PPA's for an application. When there aren't, often users create unofficial PPA's, providing the latest version of the application.

It is only in a minority of cases that it is necessary to manually download and build software from source. Building and installing from source is in some ways easier and in most ways harder than downloading a .exe or .msi installer and running it in Windows, but the experience of doing so is very, very different, so I am not sure it what way you see them as comparable.

"if Canonical doesn't provide updates for that software, then let that part of repository be comunity driven, so it will be update normally."

That is already the case. The majority of software available in Ubuntu via the official repositories is community-maintained. Software in the universe and multiverse repositories is community-maintained. Software in the main and restricted repositories is officially maintained by Canonical. Even software that is maintained by Canonical is often worked on by members of the community not affiliated with Canonical, and similarly, Canonical sometimes contributes to the development, testing, and bug-fixing of community-maintained software.

"I know about ppa's but...i use some commands for getting the list of packages and installing them back...but I must add back the ppa's."

Please explain in detail what the problem is with PPA's, and in particular, the problem you experienced. From what you have said, there does not seem to be any reason why using PPA's cannot enable you to run the latest version of the software you use.

sudo dpkg --get-selections "*" > /media/sda4/apr5.txt
sudo dpkg --set-selections < /media/sda4/list/apr5.txt
sudo apt-get -u dselect-upgrade

this commands makes my life easier when reinstalling the OS. but they don't get back the ppa's.

I don't talk about bleeding-edge programs, just stable releases.
My proposal was and improvement to repositories. Up-to-date applications, and adding new ones.

"this commands makes my life easier when reinstalling the OS. but they don't get back the ppa's."

One of those commands is run before reinstallation. If you can do that, you can also see what PPA's you have installed, then reinstall them after installation as well.

PPA's are installed by putting files in the /etc/apt/sources.list.d directory. So you could back up that directory, then restore its contents. You can do this in Nautilus (the graphical file browser), but if you want to do it in the Terminal, and you need help writing commands to back up and restore that directory, please feel free to reply requesting that. As a hint, you'd probably want to use the tar command for that (http://manpages.ubuntu.com/manpages/natty/en/man1/tar.1.html), and when you restore the files, you'll need to do it as root (http://manpages.ubuntu.com/manpages/natty/en/man8/sudo.8.html).

If you don't need the latest features, then you can run pretty current versions of programs by always using the latest stable release of Ubuntu. If you have specific programs you want to use the latest stable versions of (where that version is higher than the version provided in the Ubuntu release you're using), you can often install that with a PPA. As I explained, the changes in functionality and bugs that would be introduced by moving automatically to the next "stable" version of most software would be a problem for many users, including "power users." This would entail parts of your system breaking by themselves (because even when software is "stable", it still has bugs, and it still may work in ways that the user is not used to).

Are you arguing that the above wouldn't really be a problem? Or are you arguing that a mechanism should be put in place so that users can more easily install stable versions of software that are higher than the versions provided in their Ubuntu release (and also higher than the versions provided in any -backports repositories for their release)? If you are arguing the latter position, which seems (to me) to be more reasonable, then given the configuration that would be necessary for users to determine which packages get upgraded beyond what has been extensively tested in Ubuntu and which don't, why would using such a feature be easier than using PPA's? Why would having such a feature better harness community contributions than PPA's (which are easier to create on Launchpad than any official repository is to contribute to)?

You don't have to answer those questions here, though you most certainly can if you want, and I'll continue trying to respond constructively if you do. But these are the kinds of question you should keep in mind--and hopefully, answer clearly and compellingly--when you post your idea at http://brainstorm.ubuntu.com.