To add items to a list in bulk, or remove them in bulk. Well to do that you can use SPLinq, Server Object Model and … web.ProcessBatchData, which is the most effective. I did an experiment today. I created 1000 tasks in my task list three times and removed all items in three different ways and took time. First I put 1000 items with ajax and listdata.svc: function pad(n) { if (n >= 10000) return n; if (n >= 1000) return '0' + n; if (n >= 100) return '00' + n; if (n >= 10) return '000' + n; return '0000' + n; } var s; var counter = 0; var title = "task " function foo() { counter++; if (counter > 10000) { window.