Protocol) spam, usually using SIP (Session Initiation Protocol). This is nearly identical to telemarketing calls over traditional phone lines. When the user chooses to receive the spam call, a pre-recorded spam message or advertisement is usually played back. This is generally easier for the spammer as VoIP services are cheap and easy to anonymize over the Internet, and there are many options for sending mass number of calls from a single location. Accounts or IP addresses being used for VoIP spam can usually be identified by a large number of outgoing calls, low call completion and short call length. Academic search Academic search engines enable researchers to find academic literature and are used to obtain citation data for calculating author-level metrics. Researchers from the University of California, Berkeley and OvGU demonstrated that most (web-based) academic search engines, especially Google Scholar are not capable of identifying spam attacks. The researchers manipulated the citation counts of articles, and managed to make Google Scholar index complete fake articles, some containing advertising. Mobile apps Spamming in mobile app stores include (i) apps that were automatically generated and as a result do not have any specific functionality or a meaningful description; (ii) multiple instances of the same app being published to obtain increased visibility in the app market; and (iii) apps that make excessive use of unrelated keywords to attract users through unintended searches. Noncommercial forms E-mail and other forms of spamming have been used for purposes other than advertisements. Many early Usenet spams were religious or political. Serdar Argic, for instance, spammed Usenet with historical revisionist screeds. A number of evangelists have spammed Usenet and e-mail media with preaching messages. A growing number of criminals are also using spam to perpetrate various sorts of fraud. Geographical origins In 2011 the origins of spam were analyzed by Cisco Systems. They provided a report that shows spam volume originating from countries worldwide. Trademark issues Hormel Foods Corporation, the maker of SPAM luncheon meat, does not object to the Internet use of the term "spamming". However, they did ask that the capitalized word "Spam" be reserved to refer to their product and trademark. Cost–benefit analyses The European Union's Internal Market Commission estimated in 2001 that "junk email" cost Internet users €10 billion per year worldwide. The California legislature found that spam cost United States organizations alone more than $13 billion in 2007, including lost productivity and the