Would you buy webapps?
jacquesm: I'm not sure how 'qualified' I am to give you an answer, but I do technical due dilligence as a part of my consulting work, and some of that has been evaluating web based applications.In general the criteria I use are:  - is the team a part of the acquisition or is it just the code
  
  - how much of the knowledge about the code is present in
    the heads of the authors and how much of it is 
    transferrable

  - is the codebase in a language that you can easily get 
    developers for

  - how much time is invested in the code

  - what is the 'backlog' in terms of open critical tickets
    and such

  - what is my estimate on time to re-write the whole thing
    from scratch (some help here from wordcount and gzip)

  - how well will the current implementation scale

All those (and a whole bunch of other, but less relevant) criteria together make up the main ingredients of what goes in to determining what the value is of the code behind a web app.I hope there is something of use in there for you.