function wpcom_vip_get_term_by( $field, $value, $taxonomy, $output = OBJECT, $filter = 'raw' ) {
    // ID lookups are cached
    if ( 'id' == $field )
        return get_term_by( $field, $value, $taxonomy, $output, $filter );

    $cache_key = $field . '_' . md5( $value );
    $term_id = wp_cache_get( $cache_key, 'get_term_by' );

    if ( false === $term_id ) {
        $term = get_term_by( $field, $value, $taxonomy );
        if ( $term && ! is_wp_error( $term ) )
            wp_cache_set( $cache_key, $term->term_id, 'get_term_by' );
        else
            wp_cache_set( $cache_key, 0, 'get_term_by' ); // if we get an invalid value, let's cache it anyway
    } else {
        $term = get_term( $term_id, $taxonomy, $output, $filter );
    }

    if ( is_wp_error( $term ) )
        $term = false;

    return $term;
}