Ask HN: first few things you notice in a web site

Hackers have a very different perspective of looking at things. These are a lot of things that actual users of a web site may not look for, but hackers do :)

So, what are the first few things you note when you visit a new site? (Apart from the obvious "What is this site about?" and "How does it work?")

For example, I myself try to find out the server side technology, JS frameworks used, JS errors (if any), registration etc. I am sure that knowing these things will help me and a lot of people improve their sites.