Your web browser is just warning you that the login page is not using SSL/TLS encryption, meaning when you click 'login', your data is sent in plain text over the wire.
If someone were conducting a man in the middle attack against you while you were logging in, they'd be able to get your username and password. Likewise, your ISP could easily get your username and password if they wanted to.
Web browsers have started displaying these warnings, which I think is a really good thing. Hopefully it will force sites that haven't even implemented SSL/TLS on login pages to start to implement encryption.
Yo twoplustwo, EFF's let's encrypt is free. Free certs backed by the Electronic Frontier Foundation. Dead simple to setup. https://letsencrypt.org/
