Thanks for your answer but these are apps that won't help anyone to find a job.

i was thinking of commercial apps that need some integration work, just like Interwoven Teamsite for example
I found one of my last job in an internet web agency because they won a project of Interwoven integration and needed some Perl skills because the Interwoven API is written in pure Perl
Anyone knows some other examples of this kind of App ?

Christophe