Spamming of Usenet newsgroups actually pre-dates e-mail spam. Common reasons for blocking are spamming, trolling, and flaming. A2B initially refused, blocking only a single IP address linked to spamming. E-mail and other forms of spamming have been used for purposes other than advertisements. "Grenade spamming" or "'nade spamming" involves throwing multiple grenades into an area. LinkedIn was sued in the United States on charges of hijacking e-mail accounts and spamming. Before running, characters display "starting up" animations, to prevent players from spamming running attacks. Such practice is known as content spamming and is used to attract search engines. Improper usage includes circumventing API rate limits, violating user privacy, spamming, and sockpuppeting. Meowers retaliated against people who opposed them by spamming them. The DCU has dealt with botnets for spamming, key-logging and data ransom. This means that, unlike most ISPs, they will not terminate a customer for spamming. Then the hotlines would start spamming people. Spamming on online social networks is quite prevalent. The spamming operation was successfully shut down.