But there are so many:

Social Media channels have become such a force in the way we communicate with each other, that the number of different channels available is extensive. I thought that I would provide a list of Social Media Resources. This list was obtained from the book of Dave Evans, Social Media Marketing. I tested each one to determine if they are still available. Things change so quickly that several of the links provided in his book are no longer up.

Industry Blogs:
AdRants - http://www.adrants.com
BoingBoing - http://boingboing.net
Chruch of the Customer - http://www.churchofthecustomer.com
Customer eXperience Crossroads - http://customercrossroads.com
Social Media Today - http://www.socialmediatoday.com

Social Media Platforms
Bazaarvoice - http://www.bazaarvoice.com
BzzAgent - http://www.bzzagent.com
Jive - http://www.jivesoftware.com
Lithium - http://lithium.com
Mikons - http://mikons.com
Ning.com - http://www.ning.com
Pluck - http://www.pluck.com
ProductPulse - http://www.friend2friend.com
RockYou - http://www.rockyou.com
Salesforce.com - http://salesforce.com
Slide - http://www.slide.com

Social Networks and Services
AdGabber - http://www.adgabber.com
Bebo - http://www.bebo.com
Brightkite - http://www.brightkite.com
Del.icio.us - http://www.del.icio.us.com
Digg - http://www.digg.com
Dodgeball - http://www.dodgeball.com
Flickr - http://flickr.com
Eventful - http://eventful.com
Facebook - http://facebook.com
FriendFeed - http://friendfeed.com
Friendster - http://friendster.com
Identi.ca - http://www.identi.ca
Kyte TV - http://www.kyle.tv
Last.fm - http://www.last.fm
LinkedIn - http://www.linkedin.com
Livejournal - http://www.livejournal.com
Ma.gnolia.com - http://www.ma.gnolia.com
Metacafe - http://www.metacafe.com
Minggl - http://www.minggl.com
MySpace - http://www.myspace.com
Orkut - http://www.orkut.com
Personal Life Media - http://www.personallifemedia.com
Photobucket - http://www.photobucket.com
Ping.fm - http://www.ping.fm
Plaxo - http://www.plaxo.com
Plurk - http://www.plurk.com
Pownce - http://www.pownce.com
Seesmic - http://www.seesmic.com
SocialThing - http://www.socialthing.com
Sonico - http://www.sonico.com
Stickam - http://www.stickam.com
Stumble Upon - http://www.stumbleupon.com
Tumblr - http://www.tumblr.com
Twitter - http://www.twitter.com
Upcoming - http://www.upcoming.com
YouTube - http://www.youtube.com