Can we tell by visiting a website that it is codeignited ?

[eluser]tonanbarbarian[/eluser]
a couple of things you could look for that would "suggest" the site might be CI

1. any site with a minimum of 2 "subfolders" in the path for he majority of pages and the first 2 subfolders are always fairly descriptive
i.e. http://example.com/welcome/home might be CI
http://example.com/welcome/1234 probably is not

2. added to #1 if the url also have index.php in it that is also a possible sign, although it is not definitive as the index.php is so easy to remove from the url but I see a lot not doing it
i.e. http://example.com/index.php/welcome/home

An of course I see a lot of people who put their CI code in a subfolder for no real reason
so http://example.com/ci/index.php/welcome/home is a dead give away
http://example.com/application/welcome/home would also suggest to me CI

ideally though you do not want people to know your site runs on 1 particular technology or another so do whatever you can to disguise it, in case there are exploitable bugs found in the core of the version you are using