Code:
<mvt:item name="customfields" param="Read_Basket( 'pages_visited', g.pages_visited )" />
// Do something like an interstistial or chat
<mvt:if expr="(g.pages_visited GT 2)" >
&mvt:global:pages_visited;<br>
</mvt:if>
<mvt:assign name="g.pages_visited" value="g.pages_visited + 1" />
<mvt:item name="customfields" param="Write_Basket( 'pages_visited', g.pages_visited )" />