I've not used DNN much, so I dont know if it can do this out of the box, or if some 3rd party module is required. 

I need to make 50 sites, each with independent users, each having the same modules, but not the same content. 

So every site will have a calendar, but not the same events on the calendar. 

Also, I need some things to be static across all sites, like an Ad Sense block, or an affiliate banner.

Ideally if I needed to change out an affiliate banner or advertisement, I would hope to only have to do it once, not 50 times.

Can DNN fullfill my needs? 

Thanks in advance for your feedback.

There might be 3rd party modules out there that might satsify your requirements - or if you're comfortable making some code changes, you could possibly do what you're trying to accomplish with the core and some mods for some of the modules. DNN (Core) supports the notion of portal aliases which you could use to diffrentiate content from site to site. So you could create Portal_A, Portal_B as aliases and then train the text/html (for example) module to look out for the portal alias. This way you can setup different content based on the portal alias (as neccessary).

I've done something very similar for a customer that has 250 affliates with each of them having their own site... The content on each of the sites is different based on the stuff like company logo, pricing discounts, etc but there are common stuff that all the sites share (like layout, etc) which makes it easy to manage when you have to make an update..

Sanjay

I spoke with a couple webhosts about setting this up, and they all said they dont advise it because if one site has a problem all sites will.  What are people doing to protect themselves from any issues like this?