This page summarizes the usage of all projects on drupal.org. For each week beginning on the given date the figures show the number of sites that reported they are using (any version of) the project. Detailed usage information for each release of a project is available by clicking the project name.
Modules for uploading and managing files, and associating them with content.
overview drupal client-/server-side form validation modules
gibt auch einen guten überblick zu modulen, die gleiche funktionalität haben, die man aber noch nicht kennt
In this post I have looked at the status of the top 50 contributed modules and what state they are in.
gut zur übersicht bzw. für einsteiger