Glad to find this group. In addition to being a Drupal web developer and trainer, I'm also working on my own start up, built on Drupal.
Last summer I participated in an incubator for social enterprise startups and there was a great deal of talk about the pros and cons of using Drupal for a tech startup, particularly comparing it Rails.
The one point I like to make is that even if Drupal isn't ideal for your startup once it scales, it's hard to find a better tool for building a working prototype.
Should my own start up take off, I'm not sure whether I would keep it in Drupal or rebuild, but that's a good problem to have. It will definitely serve as a proof-of-concept. (Or proof it's a bad concept)
If you don't mind a little shameless self-promotion -- what would an entrepreneur be without some -- If any one out there has a start up and is struggling to learn Drupal, I teach a six-week online course that starts next week. A number of the people who have participated in the past, are working on start-ups and building their own site as part of the course. The course learning-community is a great place for feedback
Let me know if you have any questions.
Sam
Sam Cohen, Principal
New Media Solutions
Drupal Training & Services