I'm in the customer discovery phase for a Health IT web application concept I have. My programmer is new to web apps, but not to programming and is set up with LAM(PHP). Maybe we're a little old school, but it's proven. We're still debating weather to use a framework or to go with Rasmus's "no framework framework" approach.

Language/Framework decisions aside... my main question is about subdomain (customerx.appname.com vs subdirectory (appname.com/customerx/) models for instances of individual customers' accounts.

It seems most people are opting for the former, but I see flickr use the latter. The guys at Particletree (i.e., Wufoo) wrote a blog post about it (http://particletree.com/notebook/subdomains-development-sucks/) years ago to which they still attest.

They say the subdirectory model is much easier and faster to develop and deploy. We are developing locally on our macs and using hosted CVS.

I'm really lost on this issue as all my searches turn up stuff on SEO/SEM. Is one approach easier that the other? What about security and scalability considerations? I would very much appreciate your opinions as to the pros and cons of each approach.

As an aside, does anyone have some advice about rapid PHP deployment, i.e., pushing new features to production daily in micro iterations vs the typical milestone approach? Are there any good tools for this? What about hosts?

Thanks all,

Tim