I just came across those three very interesting articles (they are linked one among another, so finding them was easy :-)). Since I am building a new web app I have to think about the following things. And I have to do it better than I thought before I read those articles.
The well-known article Cool URIs don’t change from Tim Berners-Lee.
URL as UI is also about URI design, it contains a couple more practical tips and some reasoning that I should really consider when creating my URIs like: easy to type, all one case, hackable, no longer than 78 characters, etc…
And I should read this one about Usability of Confirmation Email and Transactional Messages, it just costs a US$100.