!New icon in SharePoint is used to indicate newly added list items. It is used as a visual clue for users. Default duration of this icon is 2 days. Fortunately, using stsadm we can update that duration or even get rid of it, if required.
To Change Duration:
You can run stsadm.exe by using the following syntax, where Number_Of_Days is the number of days that Windows SharePoint Services should display the "!New" tag:
stsadm -o setproperty -pn days-to-show-new-icon -pv Number_Of_Days -url http://Server_Address
The following example sets the expiration time to one day:
stsadm -o setproperty -pn days-to-show-new-icon -pv 1 -url http://MyServer
To Remove !New icon:
The following example removes and get rid of the icon:
stsadm -o setproperty -pn days-to-show-new-icon -pv 0 -url http://MyServer
41a82257-d293-4a0f-b786-be0625629137|1|2.0