Custom filters are short statements that you can apply to Geckoboard's Google Analytics widgets to refine the data that’s displayed and drill down to the particular metric you're interested in.
From a technical perspective, custom filters restrict the rows of data that are (or aren't) included in the result. Each row in the result is tested against the filter: if the filter matches, the row is retained and if it doesn't match, the row is dropped.
The syntax of custom filters is always the same:
name operator expression
However, depending on the type of Google Analytics widget you're setting a metric up for, the values for
expression will vary.