Why should I use Colubrid for my next web project?
First: You shouldn't use Colubrid for your webproject if you've found something better. But if you're looking for a nice small request handler, Colubrid should fit your needs.
So you're one of those PHP users ;-). If PHP is enough for you, no problem. Use it. But if you want a better scaling application and a better structure too, you should have a look at Colubrid.
Because when you develop an application for mod_python, you make it depend on it. Because this is a common problem some people at python.org proposed a web application standard called WSGI. WSGI is a very basic interface standard and can be used with mod_python, CGI and other interfaces for webserver communication.
You can use WSGI without Colubrid or frameworks like django, but it isn't easy to use. For example, you have to parse the query string and form data on your own...
Good question. I for myself use django for many applications. But for pocoo I was looking for something simpler, to avoid making pocoo depend on a framework.