Nokia has closed the Nokia Store for Symbian and MeeGo developers on 1. January 2014. Beside the signing problem from this point there was and is no real alternative to publish Symbian apps in the same way the Nokia Store provided (MeeGo users should have a look at openrepos.net). As I personally currently do not see a real alternative to Symbian for me I still plan to use my 808 PureView and develop apps for it.
Without the Nokia Store it is the same situation we had before what some are naming as on of the reasons why Symbian never had a huge app ecosystem (there may be other reasons, but this is not the topic here ;) ).
Already since summer 2013 I had the idea to create an app with that users would be able to manage all my apps. With the Store-close announcement this idea moved on and reached the point to create an alternative Store where developers are able to publish, maintain and update their apps. While releasing the first app as a self-signed version in December I saw what a Store like that has to offer to provide a platform for the future. Missing signing possibilities mean that each app which was released in the Nokia Store and gets an update after it has to be first uninstalled and then the new version installed. This includes downloading, moving and launching the sis-installer, what is especially not easy for "noobs".
Here is where AppList attempts to find a solution. Developers can manage a self-signed, unsigned and Nokia Store version and AppList helps users to upgrade between different versions. It further provides nearly the same UI you already know from the Nokia Store client, so transition is easy.
The web interface you have currently opened in this tab is not based on the Nokia Store web design. Instead I looked at all major stores to see who has done the best job and although I am not the biggest Windows Phone fan I have to admit that the web version of the Windows Phone Store definitely has the best look in my opinion. So the web UI of AppList is based on the Windows Phone Store web UI.
Further the database is based on Steve Litchfield's curated App Store, because the intention is also to collect the "crème de la crème" of available and still working Symbian apps together.