Looking for feed back on a guestbook

Cobo has asked for the wisdom of the Perl Monks concerning the following question:

It has been a while since i last made something with Perl so I decided for a brief refresher to make a simple guestbook. I was just wondering if any one had any comments or if any one could see any huge security holes.

#!/use/bin/perl -w
use strict;
use CGI ':standard';


print header();
print start_html();

print "<html><head><title>Thanks for Signing!</title></head>";
print "<body bgcolor=black text=white>";

my $q=new CGI;
my $name =$q->param('name');
my $mail =$q->param('mail');
my $message =$q->param('message');



      print "<center><p>Thanks for signing my guestbook, your message 
+has been posted! $name!</center></p>";

# REMOVE THIS COMMENT TO ACTIVATE CENSOR if ($message =~/badword/i or 
+$message =~/badword2/i or $message =~/badword3/i) {$message =~ s/badw
+ord/bleep/ig; $message =~ s/badword2/bleep/ig; $message =~ s/badword3
+/bleep/ig;};

if ($message =~/</ or $message =~/>/) {$message =~ s/</&lt;/g; $messag
+e =~ s/>/&gt;/g;};

if ($name =~/</ or $name =~/>/) {$name =~ s/</&lt;/g; $name =~ s/>/&gt
+;/g;};

if ($mail =~ /</ or $mail =~/</) {$mail =~ s/</&lt;/g; $mail =~ s/</&g
+t;/g;};

if ($message =~ /\(b\)/i or $message =~ /\(i\)/i or $message =~ /\(\/i
+\)/ or $message =~ /\(\/b\)/) {$message =~ s/\(b\)/<b>/ig; $message =
+~ s/\(i\)/<i>/ig; $message =~ s/\(\/b\)/<\/b>/ig; $message =~ s/\(\/i
+\)/<\/i>/ig;};


if ($message =~ /\(red\)/i or $message =~ /\(\/red\)/i) {$message =~ s
+/\(red\)/<font color=red>/ig; $message =~ s/\(\/red\)/<\/font>/ig;};

if ($message =~ /\(red\)/i and $message =! /\(\/red\)/i) {$message=$me
+ssage."</font>"}; 


print    "Name: $name <br> Email: $mail <br> Message: $message";
open HTML, ">>../gbook.html" or die $!;
print HTML "<i>Name:</i> $name <br> <i>E-Mail: </i>$mail<br> <i>Messag
+e: </i>$message <p>";
close HTML;          
        



print "</BODY></HTML>";
[download]

Any comments would be appreciated, thanks.

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