A couple of weeks back Andy Mahood posted an interesting question that cought my eye:
Is there a blog explaining report url params ?isdtp=mn shows report without headers, ?isdtp=nv shows no header and fewer colours #askforce
It's a question I've asked myself in the past, and while my experience with the isdtp param isn't exhaustive I have managed to get it to do what I want on more than one occasion.
A word of warning before I explain what this parameter does, this is 100% unsupported and you should avoid using this whenever possible. Salesforce may break it's use on pages without much warning, so be warned this shouldn't be used in anything that's mission critical.
With that out of the way the isdtp parameter is a special parameter used in the service cloud console and the plain old console tab to make salesforce pages display without header, sidebar, and sometimes in a simplified style. Adding a ?isdtp=<option> or &isdtp=<option> to any salesforce page (even visualforce! ) will dramatically change the way it's rendered.
There's three useful options for the parameter that I've found so far:
vw - used by the service cloud console. This is the only option that supports the new aloha theme. It strips the salesforce header and sidebar from the page. There's some small functionality degradation (enhanced lists are not longer enhanced, some ugly styles here and there) but this is your only option if you want to include chatter support through isdtp.
mn - the second most functional, but far behind the vw option. Like vw the header and sidebar are stripped out, but in addition chatter will always be removed as well, and the old salesforce theme (pre-aloha) will be used.