From http://wiki.vtiger.com/archives

About

Custom filter is made available in ListView of the module to allow record filtering based on a condition. It helps you view preferred columns of the record quickly also control the filtering criteria.

How To create Custom filter

Click on New link to create the filter.

You can select the columns to be displayed in the ListView when filter is selected.

On save you will be able to see the filter in action.

Advance Filter

You can edit the existing filter created earlier and set the Advanced Filtering option (rules).

You can set the condition for filtering as shown in the screen shot below.

After save, the Listview filter the records based on the criteria set in Advanced Filter.

Standard Filter

This option filters the records depending upon any Date field for a particular period.

How To Use

you can find the following options in standard filter

Select a Column -Pick List which will show all the date fields present in that module,

Select Duration -Pick list where we have given some default Duration like Last 7 days,Last 30 days, Next Week etc,if you will choose any value the start date and End date will select automatically.

Star date and End date- You can give the value manually in these option or If you will select a Duration these fields will automatically filled.

For e.g in the below screen shot in products module I have Select Duration as Previous FY(Previous Financial Year) and the start date and end date automatically taken its value.

After saving the filter if you will go to List view and select this filter you can see only those products where the Sales Start date lies between 2008-01-01 and 2008-12-31.

List in Metrics

This option if enabled for a customview the count of filtered records will be shown in the “Key Metrics “ widget on the Home Page.

Set as Default & Set as Public

To know about this please go here