I propose that we add an optional attribute to the <a> (link) tag in HTML. Its name is 'vote'. Its value can be "+" "0" or "-", representing agreement, abstention or indifference, and disagreement respectively.
An untagged link is deemed to have value "+".
Additional human-readable commentary can be added using the existing 'title' attribute, which most browsers show as a rollover.
<a href="http://ragingcow.blogspot.com" vote="+" title="neat spoof">Raging Cow</a>yields
<a href="http://ragingcow.com" vote="-" title="nasty corn syrup drink">Raging Cow</a>yields
Points that keep coming up:
Why only + and -? How about something more nuanced?
The point of this is to provide a strong yes/no response. Finer-grained measures of agreement don't make much sense on an individual basis; aggregating many votes is more interesting. For example, consider how eBay's user rating system has been reduced to a like/dislike switch by users. The 'Ayes, Noes, abstentions' model has served well in politics.
There are much richer ways to express this idea and similar ones using RDF and semantic web ideas
Indeed there are, but typing them by hand and remembering them is beyond most mere mortals, and automated tools don't do this either. This is meant to be very simple, memorable and easy to type in the current generation of blogging tools, that largely need manual entry of URLs.
I'd like some visual representation on the page of these different types
You can do that by defining 'voteyes' 'voteno' and 'abstain' classes in css and applying them to the post as well.
Won't all this negativity lead to trolling and flame wars?
Trolling is a problem already - Google's PageRank rewards being linked to, so notoreity is valued as highly as popularity. This leads to a 'no publicity is bad publicity' approach.
For relentless positivists, the '0' and '-' values could be taken as signals meaning "don't index this link". For Vote tallying, however, positive and negative responses are both valuable and clear.
The possibility of a personally filtered search, which reflects your own values expressed by your own links is gretaly enhanced by the ability to define neagative links as well.
Exhaustive taxonomy of link types Far too much complexity.
An earlier call for this kind of thing
John Lebovsky's variation on a theme
Steven Johnson channels Vonnegut on Karasses & Granfalloons