URL shorteners are already starting to be seen by the anti-spam community as being a little bit like open SMTP relays.

Several of my customers have been listed on the SBL because they ran unauthenticated URL shorteners, and of course, those shorteners were used to get around anti-spam URL blacklists.

Do you mean that their server IPs got blacklisted? Or did the URL shortener domain just get added to a URL blacklist?

Both, if I remember correctly.

Though interestingly, he doesn't really mention 301 redirects. Is the point that URLs shouldn't change, or that changing URLs shouldn't break the web (or a little of both)?

Considering that no URL shortener I know of will actually let you change the underlying URL it points to, unless the hosting service decides to change what the underlying URL actually points to (tsk tsk), the shortener is pretty much a canonical pointer to that data, despite the fact that the hash doesn't often give much information about the underlying data.

Also: see http://www.301works.org

If you actually visit 301works.org you will notice that there are a whopping _seven_ URL shorteners that have uploaded any data at all in the past 6 months:

- rn.tl / lensrentals.com

- nbl.gs

- qr.cx

- tiny.cc

- urlcut.com

- url.ie

- va.mu

And to be honest, those 7 shorteners aren't exactly big fish in the URL shortener business.

I did, and it seems that at least bit.ly data is uploaded daily, but your point still stands - 301works does not have anything close to 100% shortener coverage.

http://www.archive.org/search.php?query=collection%3A301work...

Unfortunately that is not bit.ly uploading any data. It is the effort of a few people (me included) that scrapes bit.ly and uploads it to archive.org.

Despite claiming otherwise, bit.ly hasn't uploaded a single short url to 301Works yet.