I have previously blogged about top dot-com flops.  By chance I came accross this great round-up of failed startup post-mortems on ChubbyBrain.  The list includes, among others, the following:

• Wesabe
• ArsDigita
• RiotVine
• Nouncer
• BricaBox
• Boompa
• Xmarks
• EventVue
• YouCastr
• IonLab
• Devver (and here is my take on its failure)
• Monitor110 (see here for my own take on its post-mortem)

An article (also pointing to the above source) on GigaOm featured information about post-mortem of the infamous StandoutJobs . As for main reasons why statups fail, have a look at Paul Graham’s article and my previous blog post. Finally, here is good set of lessons from Mark Goldenson, founder of PlayCafe (one of failed startups on the above list). I especially like his “Set a dollar value on your time,” which helps prioritize tasks and clarify what is and is not important for your business.