Pagerank 5 Forums that you can use to build your search engine rankings. Create profiles in these forums and add your link with proper anchor text to your profile and signature (if available). Then post relevant content in the forum or get a list of all your profile URL’s and create an RSS Feed and Ping this out.
 

List of Pagerank 5 Forums

http://forum.keanemusic.com

http://forum.abestweb.com/

http://forum.purseblog.com/

http://forum.ctc.org.uk/

http://steadfast.net/forum/

http://www.hometheaterforum.com/htf/index.php

http://www.laserforum.org

http://luminous-landscape.com/forum/

http://www.thaivisa.com/forum/

http://www.avsforum.com/avs-vb

http://blenderartists.org/forum/

http://forum.rpg.net

https://www.myinfoline.com/forum

http://forum.japantoday.com

http://forum.notebookreview.com

http://tmp.garyr.net/forum/

http://forum.419eater.com/forum/

http://extjs.com/forum/

http://forum.bitdefender.com

http://fpa.vnexpress.net

http://www.wongkarwai.net/forums

http://www.informatik-forum.at

http://www.hmailserver.com/forum

http://www.goldenvoice.com/forum

http://forum.donnavventura.com

http://forum.blacknight.com

http://forum.axishistory.com

http://www.retailmenot.com/forum

http://forum.whmcs.com

http://www.3g.co.uk/3GForum

http://www.dnforum.com

http://forums.tizag.com

http://www.deepburner.com/forum

http://forum.xda-developers.com

http://www.cre8asiteforums.com/forums

http://forums.seochat.com

http://submitexpress.com/bbs

http://www.highrankings.com/forum

http://www.v7n.com/forums

http://www.webmaster-talk.com/

http://www.daniweb.com/forums/

http://www.webmaster-forum.net/

http://forum.newsgator.com/

http://www.feedforall.com/forum/

http://www.bloggerforum.com/

http://www.bloggertalk.com/

http://www.rss-forum.de/

http://www.cookingjunkies.com/

http://www.htmlforums.com/

http://forums.afterdawn.com

http://www.aqua-soft.org/board/

http://softwarecommunity.intel.com/isn/Community/en-us/Forums/

http://forum.notebookreview.com/

http://www.techsupportforum.com/

http://forums.worldofwarcraft.com/

http://www.theadminzone.com/forums/

http://forums.comicbookresources.com/

http://www.gardenstew.com/

http://www.movie-list.com/forum/

http://www.codingforums.com

http://codingforums.com

http://bbs.eol.cn

http://homeofficeforum.ca.com/homeofficeforum

http://eudorabb.qualcomm.com

http://forum.limewire.org

http://forum.aumha.org

http://www.419legal.org

http://extjs.com/forum

http://www.yumichong.com

http://en.forum.laptop.org

http://forums.fatakat.com

http://www.techimo.com/forum

http://www.sanparks.org/forums

http://chinalanguage.com/forums

http://forums.pligg.com

http://www.hockeydb.com/vb

http://forum.physicianspractice.com

http://forum.domaingo.de

http://forums.zmanda.com

http://inside.insa-lyon.fr

http://www.ubcbotanicalgarden.org/forums

http://forum.nashuatelegraph.com

http://www.pcwelt.de/forum

http://forum.kinopolska.pl

http://forum.ilmeteo.it

http://www.colboard.com

http://forums.seedsavers.org

http://forum.redlers.com

http://www.googlecommunity.com

http://forum.mikrotik.com

http://forum.meteonetwork.it

http://www.haydoo.com/forum

http://yumichong.com

http://forums.mozillazine.jp

http://forums.multimap.com

http://forums.kayako.com

http://www.finlandlive.info

http://www.forumsig.org

http://duc.digidesign.com

http://www.security-forums.com

http://forum.rp.sg

http://www.webhostingcommunity.com

http://www.iesaf.fi/sauna

This will drastically increase your back links and search engine optimization benefits.  If you find any broken links or want to add a new forum to the list please submit it in the comments section and if it is appropriate i will add it to the list of SEO friendly forums.