This post is on the distinctions between specific web sniffers: those of induction nature, and those of condenser or proxy nature.
WireShark is an all-inclusive network protocol analyzer. It works to display all the protocol layers including application layer protocols (HTTP and SSL). Though it is well able to capture a multitude of protocols, we focus on the HTTP, which is vital to Web Scraping. Other traffic analyzers are reviewed here.
This post deals with LiveHTTPHeaders, the FireFox add-on, by Daniel Savard. This built-in tool is designed to show live HTTP headers and traffic content, too. This tool stands among other simple and multy-functional HTTP traffic analysers.