Note: This snippet is no longer needed as Jetpack includes Search Pages by default now.

By default, Infinite Scroll is only active on your site’s home page as well as on the archive pages. You can, however, use the infinite_scroll_archive_supported filter to add support to other pages:

function tweakjp_custom_is_support() {
	$supported = current_theme_supports( 'infinite-scroll' ) && ( is_home() || is_archive() || is_search() );
	
	return $supported;
}
add_filter( 'infinite_scroll_archive_supported', 'tweakjp_custom_is_support' );

If you’d like to change the default credit link appearing in the Infinite Scroll footer, you can use the infinite_scroll_credit filter, like so:

function tweakjp_cust_credit() {
	return '<a href="http://example.com">My Custom Link</a>';
}
add_filter( 'infinite_scroll_credit', 'tweakjp_cust_credit' );

Once you add that code to your theme’s functions.php, a new link will appear instead of the default “Powered by WordPress” link.