The weDownload is a product used by developers to monetize their products. For example, you will see weDownload in action when you want to install another application. During the first phase of install, you will see various offers related to promotions or software downloads. For every installation of those applications, the developer of the main software has the chance of earning additional money.
However, these applications are considered adware/malware and it's recommended to remove them as soon as possible. You can use AdwCleaner for that purpose.