Consider using only the character set in NewBase60 to ensure all your URLs are print-safe and unambiguous. If you follow the NewBase60 algorithm it has built-in error correction (e.g. O is considered the same as 0)

Character set: [0-9A-HJ-NP-Z_a-km-z]

More background: http://ttk.me/w/NewBase60

I like that so much. Thanks, for bridging the gap between the online and the tangible. Feedback: find a way to market it really well, because it would be cool to see lots of people walking around with these. Also, maybe consider "couples shirts" as sometimes couples like to wear shirts that reference each other, a la the classic (?) "I'm with stupid" :) Conferences could be another big win for you -- bulk orders, and maybe you could "include" shirt urls atop another suppliers merch so everyone can be "URLing" their wares on their backs for all to look up. It would be cool to have a "shirt url" spotted-at Instagram feed, like, "post some pics of where you wearing your shirt url, <x> one gets free special edition shirt." x in superlative of your choice :) The name is really good. This whole thing made me smile so I'd say you're definitely onto something if you can make people feel good.

You might consider adding an option to display a QR code on the shirt instead of a URL. It would be really cool if you could also provide the ability to embed a logo/icon into the QR code (a la http://hackaday.com/2011/08/11/how-to-put-your-logo-in-a-qr-...). Would be good for companies.

I was a little disappointed that it isn't possible to order shirturl.com/1337 (minimum 5 characters).

The 'Home' link in the footer is a 404 (https://shirturl.com/home).

I think you should add a privacy policy.

That said, good luck!

Wow very cool idea.

As others have mentioned QR code would be cool but maybe hard to accomplish with wrinkles in shirts, etc. If you can get it to work, a companion app would be cool. See someone wearing the shirt, scan the code, see the message. Of course with augmented reality it would be even cooler!

Cute idea. I like it.

Dress up your page a bit and drop it on product hunt. Im sure people will love it on there.

This is a side project where we are trying a new concept and I would love some feedback. If you want to try it, use discount code 'HACKERNEWS'.

I don't think QR-codes wouldn't be an improvement at all. They are ugly and akward. Instead consider printing the URL on the back as well.

The concept is nice. People at Product Hunt tend to appreciate these kind of things well. Hope you are on track with posting on PH as well.

You need to printing QR codes for that, not just the plain text URL.