Here are some tools and hints to help you identify if a web site is WordPress and how the site was put together.
Here is a tool which will tell you if a web site is WordPress and if it is it will tell you what WordPress Theme was used. It give information about the Theme and Theme developer. AND it given some indication of the plugins that were used.
WordPress Theme Detector – try it this is very cool. One thing I am seeing is if the site is using CloudFlair this tool does not get much theme information – other than the theme name
Here is another one Is It WP shows if a site is WordPress or Not, the hosting company and has a who is link – it also gives the theme and plugins that are being use – does not seem to work as well as WordPress Theme Detector
Here is yet another theme detector What WP Theme is That – quick however like the others does not seem to get a lot of theme information if CloudFlair is used
Here is a tool that give a lot of information about sites Built With – this one does not identify themes but it does identify if it is WordPress and gives information about analytic, tracking, plugins and more – also tells a lot about non WP sites.