Change Detection and Notification of Webpages: A Survey <s> INTRODUCTION <s> We are witnessing a widespread of web syndication technologies such as RSS or Atom for a timely delivery of frequently updated Web content. Almost every personal weblog, news portal, or discussion forum employs nowadays RSS/Atom feeds for enhancing pull-oriented searching and browsing of web pages with push-oriented protocols of web content. Social media applications such as Twitter or Facebook also employ RSS for notifying users about the newly available posts of their preferred friends. Unfortunately, previous works on RSS/Atom statistical characteristics do not provide a precise and updated characterization of feeds' behavior and content, characterization which can be used to successfully benchmark effectiveness and efficiency of various RSS processing/ analysis techniques. In this paper, we present the first thorough analysis of three complementary features of real-scale RSS feeds, namely, publication activity, items structure and length, as well as, vocabulary of its content which we believe are crucial for Web 2.0 applications. <s> BIB001 </s> Change Detection and Notification of Webpages: A Survey <s> INTRODUCTION <s> Digital documents are likely to have problems associated with the persistence of links, especially when dealing with references to external resources. People keep track of various webpages of their interest using distributed digital collections and without possession of these documents; the curator cannot control how they change. In the current context, managing these distributed digital collections and getting notifications about various changes have become a significant challenge. In this paper, we address the architectural aspects of change detection systems and present optimized change detection architecture, including a web service and a browser plugin, along with an email notification service. We have performed an experimental study on our hybrid architecture for change detection in a distributed digital collection. The proposed method introduces a preliminary framework that can serve as a useful tool to mitigate the impact of unexpected change in documents stored in decentralized collections in the future. <s> BIB002
The World Wide Web (Web in simpler terms) is being evolved in a rapid pace and keeping track of changes is becoming more challenging. Many websites are being created and updated on a daily basis with the advancement of tools and web technologies. Hence, websites at present have become more dynamic in nature and their content keep changing continuously. Many users are interested in keeping track of the changes occurring in websites such as news websites, booking websites, wiki pages and blogs. Majority of the users keep track of these websites and get the latest updates using bookmarks in web browsers or register to "Really Simple Syndication (RSS) feeds", originally known as "RDF Site Summary" [RDF Site Summary (RSS) 1.0 2000]. Web syndication technologies (e.g.: RSS, Atom) emerged as a popular means of delivering frequently updated web content on time BIB001 . Users can subscribe to RSS or Atom feeds and get the latest updates. However, when considered from a perspective of webpage change detection, RSS feeds have many potential issues. For example, graphics may not appear in certain RSS feeds and only the update is provided. Sometimes it is difficult to identify the source of an RSS feed item, as certain RSS feeds do not display the actual Uniform Resource Locator (URL) or name of the webpage from which the update originated. This may cause confusions among users as they cannot identify the webpage to which the update belongs to. Users are not able to compare the new content with the previous content if required. A study carried out to characterize web syndication behaviour and content BIB001 shows that the utilization of fields specified in the XML specification of RSS is less, which can result in missing information, errors and uncategorized feeds. Furthermore, services such as "Google Reader" have been discontinued due to the declining popularity of RSS feeds  . In the current context, managing and using bookmarked websites and RSS feeds have become a significant challenge and people are continuously seeking better and convenient methods. "Change Detection and Notification (CDN) systems" BIB002 ] make it easy for users to get notified about changes which have occurred in webpages, without having to refresh the webpage continuously. These systems are now automated by many CDN systems. "Google Alerts" [Google Alerts 2003] , "Follow That Page" [Follow That Page 2008] and "Visualping" [VisualPing.io 2017] are some of the most popular CDN services which are used by many users to get updates about content changes that occur in webpages.