There are a few definitions I can provide for terms and concepts which either do not appear in the dictionary yet, or never will:

Link Bait 
 
No, this is not about fishing, or even phishing, this is about link building.  Link-bait is the title of an article or blog post that is designed to get people to read it and then link to it, creating traffic and link popularity for the source.  It may also be for the purpose of getting a message out and read widely by getting it reprinted (cyber-published, blogged, etc).  Hint: ‘link bait’ may not have anything to do with the content of the article or post, as long as it still accomplishes the intended purpose.
 
Social Bookmarking
 
No, it is not about books, print, or anything like that:  Social bookmarking refers to sites like digg.com, stumleupon.com, and a plethora of others with slightly different approaches.  These sites are designed to enable web-surfers to take advantage of each other’s time surfing and searching, and to minimize the time required for them.  This is done by following like-minded peoples’ bookmarks (links and notes to and about websites)(see digg.com), by browsing pre-edited categories that have been screened for content quality (AssociatedContent.com, for example); and/or by some other method other than endless keyword searching (Stumbleupon.com)
 
Spam
 
Doing the above without conscience or regard as to as to quality or content, for personal gain.
 
Viral Marketing
 
This refers to the art and science of doing the above on purpose in such a way as to start a chain reaction online, so that once started, the campaign to get links and or traffic and grows on it’s own, like a fire, or more specifically, a virus, as a virus will grow for a time then eventually either run its course or kill the host. 
 
An example of all three put together is to write a post, with a title which has nothing to do with the content, but gets people to read it, with content that is so compelling that everyone bookmarks it at digg.com, so it is so popular on digg that it hits the front page of digg, resulting in 50,000 qualified hits within one hour, which crashes the server!  Here is a real life example: we had a client  who blew the whistle on Enron: type their name into Google, and you will find a lot of good stuff on the first page.  When they came to us that was not the case: see the Google search: ‘social media bomb’
 
Notice the article:
 
 
Barry Hurd was working for me at the time, and I asked him to write an article that we would try to get on top of digg to push negative press on USA Today ( a very well optimized, strong blog) about the Gal who blew the whistle on Enron  off the first page.  Because our blog is syndicated and shows up on Web-pro news and others, it got so many ‘diggs’ (social bookmark votes) that it literally crashed our main server, not to mention doing a great job of being reprinted all over and getting the message out.  (You can read the rest of the story in the article)
 
Learn more about Social Media Marketing at our group at Realtown:
 
Israel Rothman is a well known Internet entrepreneur and author for several online magazines.  He has started several businesses and is currently CEO of LLC, Social Media Marketing and Website Design company.SocialMediaSystems.com