What's the purpose/meaning of "link rel" ??

The thread's title says it all: what's the purpose of link tag's "rel" attribute, are its possible values arbitrary/optional, or are there any rules that apply to it ?? I mean I know how/when to use it, but I am interested in "theory" behind it ...


For instance, one such example in which I've seen it being used:

<link rel="start" title="start" href="/" />

Code (markup):

Or in a case well-know to all of us when specifying an external stylesheet:

<link rel="stylesheet" type="text/css" href="root.css" title="style" />

Code (markup):

P.S. -- Oh, and maybe also this: what's the meaning of link tag's "rev" attribute?

I've seen it being used in a case like for instance this example below:

<link rev="made" href="mailto:someword@somedomain.com" title="made" />

Code (markup):

tayiper

 

http://www.w3.org/TR/html4/struct/links.html#adef-rel

 

Thanks much for the link Brian !!


tayiper

 

you're welcome

 

yet read that page on W3C): are the attrubtes' names and their values arbutrary or pre-set or pre-defined ??


thanks again, tayiper

 

My understanding of the theory behind rel=nofollow is that Danny Sullivan of SEW was pressing Google and probably the other SEs to come up with some way of preventing blog spam by taking the trust factor out of links posted on blogs. By getting the SEs to accept it, it then became an accepted standard over time. So that value "nofollow" originated from this idea but I wouldn't say it's totally arbitrary but it could be rel="notrust" or rel="white_elephant" or whatever you want as long as it gets accepted. Other names and values are interpreted by the browsers for the display or functionality of the link. I think these protocols come about from RFCs (request for comments):
http://www.rfc-editor.org/rfc.html

 

That should be something like this: "One more thing. I started thinking (after I read that page on W3C): are the attrubtes' names and their values arbutrary or pre-set or pre-defined ??"


tayiper

 

http://reference.sitepoint.com/html/link/rel