Earlier this week, I wrote an article over on the FliteHaus blog comparing responsive, adaptive, and mobile optimized sites. In addition to defining what they are, I also gave examples of when to use each for your latest project.
Admittedly, the article was written for current and prospective clients, but I think the article offers some high-level insight into what each is and the situations for which each is designed. If you’re new to designing for the modern web, or just want to reaffirm your stance on each architecture, it’s a decent read.