Call centers use IVR systems to identify and segment callers. The names of all incoming telephone callers are recorded on a central log. It features Savage answering anonymous questions left by callers on a voice recorder (answering machine). The layers are symmetric, because in a telephone system callers can also be called. Hotlines were established to calm down worried callers. Businesses looking for local callers tend to connect to a "1300" number. Tamarins are able to identify the sex of unfamiliar callers too. These include thieves, prank callers, and vandals. In June 2013, Whitepages acquired Mr. Number, an Android app for blocking unwanted callers. Additionally, Minaj gave advice to callers about their sex lives. A few of the callers polled considered Janet as "funny and appealing". UAWs also are more prone to being swindled out of money from cold callers. DBChIP and MAnorm are examples for one stage differential peak callers. Some callers, as well as host Howard Stern, came to Plato's defense. Examples for two-stage differential peak callers are ChIPDiff and ODIN.