check_follow.pl

#!/usr/bin/env perl
use strict;
use warnings;
use WWW::Mechanize;
$|=1;
my ( $user, $pass ) = ( 'user_id','user_password' );

my $mech = WWW::Mechanize->new();
#$mech->agent_alias( 'Windows IE 6' );

$mech->get('http://twitter.com/login');

$mech->submit_form(
        form_number => 2,
        fields => { 'session[username_or_email]' => $user,
                    'session[password]' => $pass,
        },
        button => 'commit',
        );
die unless $mech->success;

my %users;
my $url = 'http://twitter.com/following';
do {
    $mech->get( $url );
    die unless $mech->success;
    #print $mech->uri(),"\n";
    my $html = $mech->content();
    my @items = $html =~ m{<tr id="user_\d+".*?</tr>}sg;
    foreach my $item ( @items ) {
        my ( $info, $name ) = $item =~ m{class="(.*?)".*?<span class="label screenname">.*?title=.*?>(.*?)<}s;
        my $is_friend = ( $info =~ m/direct-messageable/ ? 1 : 0 );
        print "$is_friend $name\n";
        $users{$name} = $is_friend;
    }
} while ( $url = $mech->find_link( text_regex => qr/Next/ ) );

printf "\n%d/%d  Cross following rate is %2.2f%%\n",
       scalar( grep { $users{$_} } keys %users ),
       scalar( keys %users ),
       100 * scalar( grep { $users{$_} } keys %users ) / scalar( keys %users );