[ikopylov]

Это на все 100% использовать не стоит, каждый корректирует для себя

Prevent search engine spiders from visiting areas of your forums that they do not need to spider

robots.txt ориентированный для vBulletin

Нажми для просмотра

Create a robots.txt file with the following and upload it to your public_html directory:
User-agent: *
Disallow: /forums/admincp/
Disallow: /forums/clientscript/
Disallow: /forums/cpstyles/
Disallow: /forums/customavatars/
Disallow: /forums/customprofilepics/
Disallow: /forums/images/
Disallow: /forums/modcp/
Disallow: /forums/ajax.php
Disallow: /forums/attachment.php
Disallow: /forums/calendar.php
Disallow: /forums/cron.php
Disallow: /forums/editpost.php
Disallow: /forums/global.php
Disallow: /forums/image.php
Disallow: /forums/inlinemod.php
Disallow: /forums/joinrequests.php
Disallow: /forums/login.php
Disallow: /forums/member.php
Disallow: /forums/memberlist.php
Disallow: /forums/misc.php
Disallow: /forums/moderator.php
Disallow: /forums/newattachment.php
Disallow: /forums/newreply.php
Disallow: /forums/newthread.php
Disallow: /forums/online.php
Disallow: /forums/poll.php
Disallow: /forums/postings.php
Disallow: /forums/printthread.php
Disallow: /forums/private.php
Disallow: /forums/profile.php
Disallow: /forums/register.php
Disallow: /forums/report.php
Disallow: /forums/reputation.php
Disallow: /forums/search.php
Disallow: /forums/sendmessage.php
Disallow: /forums/showgroups.php
Disallow: /forums/subscription.php
Disallow: /forums/threadrate.php
Disallow: /forums/usercp.php
Disallow: /forums/usernote.php If you use something other than /forums/ for your forums directory, you will want to adjust the paths accordingly (just like /usernote.php if your forum is in www root)

материал взят отсюда, советую почитать, очень полезная информация, как для 3ки так и для 4ки, правда на англ.