In Sitecore, it is possible to configure a web site to take Items directly from the content authoring database, thus eliminating the need for publishing. For instance, this is the way the Sitecore client site works on a core database. This can be done with the website by simply changing the database="web" attribute to database="master".
But in this case, you will notice that Publishing and Lifetime restrictions (such as the Never publish checkbox or the Valid to lifetime field) don’t work anymore, as long as the site takes Items directly from the master database and the publishing process, which takes Publishing and Lifetime restrictions into account, is omitted.
Setting the filterItems attribute to “true” allows preserving the Publishing and Lifetime restrictions when running in the mode described above.
Default value : “false”.