Firefox did that to me with Gmail the other day, as well as with ESPN. I think it is a random thing in Firefox, I haven't given it much thought. I guess that is only helpful if you are using Firefox as well though.
I use chrome. It does that to me with google and youtube randomly, it says that the certificate of authentisity isnt validated or something like that. But right now there was just a yellow triangle on the URL bar saying that there was unsafe content on the site.
My girlfriend advised me to close the browser and open it again, then the warning thing was gone. Any one have any idea why? Or how that works?
I use Fire fox and it has a nice add ons tools that solve all my problem. Well I have been using this Firfox for one year and I have never switch to another browser.