how do i create this forum feature

[Anon]

Hi,

i'm making a forum, and i was wondering how i should create the feature that the lightbulbs in front of a forum on the forum index change when there are new topics/replies since your last visit....

my idea would be to do it with cookies and if statements,
how would you guys do it?
(php + mysql)

[Anon]

Well, you'd have to know the date and maybe time of the user's last visit, so cookies sound like the easiest idea. The only other way I can think of, is to hold some kind of access log on the server, which means signing in / authenticating and all that game. Go for cookies.