Difference between a Website Activity and HTML Archive Activity
The main difference between the Website Activity and the HTML Archive Activity is where the physical web page content resides.
The Website Activity is designed to display a website that has been published to a web server. You can think of it as any url (such as http://www.andromo.com) that you browse to on a computer or device using a web browser such as Internet Explorer, Firefox, Chrome, Safari etc. Just like a web browser, when you visit the website, the pages are downloaded to the device so you can view them locally. This type can be useful if you want to reference content that is either not your own, or that you've already published online that you keep up-to-date.
The HTML Archive Activity is also designed to display web content, however it differs in where the content physically resides. Instead of the html pages existing on a web server and downloaded to the device, the HTML Archive Activity provides the ability to store the HTML content within the application so it can be read directly from the device. To implement this type, you would create the same html stucture that you would use if you were publishing it to a web server (making sure relative pathing is used), but instead create a zip archive of the html content files. This type can be useful when you want to include custom content that you don't want to make available online, or for performance reasons, since loading the content directly from the application will be more responsive than having to download it.