[otrs] "Link" menu

Hi, I have never used up to now the "Link" feature of a ticket. As I can guess it is used to link a ticket to several other ones. But I still can not get the sense of this. Would someone like to explain the usefulness of this feature? -- Best regards, Teodor Georgiev Information Services Plc. Tel : +359 2 96562008 Mobile: +359 887 508989