- Twitter links are almost never clicked on outside of the first several hours. 301 redirects will cause search engines to use the canonical URL as well. This Link Rot Apocalypse is largely a bunch of nonsense.
- People use short URL services to get analytics on the data they're sharing, not just to shorten the URL. People like their click stats.
People are overstating both the ephemerality of shortener sites and the longevity of original URIs.
Got data to back that up?
The click stats are really great for addictiveness.
I think rev="canonical" is not a great solution either.
BTW, I meant Link Rot Apocalypse facetiously.
You wouldn't need any thing special, and people wouldn't need to shorten your url.
Someone else goes to red things then bags than item 5 /red/bags/5
You end up with duplicate content issues and the possibility of having your search engine score split between the two pages.
With canonical you can say on both pages that /items/5 is the real url and thats the one that will get the search score + be indexed most likely.
I was pretty convinced that canonical was a solution in search of a problem, but at least joshu's opening salvo, the DiggBar brouhaha, and the resultant conversation has shown one use for it.
The proposal mixes alternative urls with the idea of a canonical url. Besides being damn confusing (remembering the difference between rel and rev), it opens up security issues. Moreover, the 'rev' attribute is not included in HTML 5, making this proposal obsolete before it even starts.
I've written up a longer explanation of these problems on my blog for anyone interested:
http://cubiclemuses.com/cm/articles/2009/04/12/short-and-can...