I've heard that Ubuntu has some sort of "phone home" system that is enabled by default. The kind of stuff that passes along performance information and that type of things to Canonical. I don't know if this is true or not, but if it is happening, how would one disable it for a secure environment?
I'm not worried about something like this https://www.eff.org/deeplinks/2012/10/privacy-ubuntu-1210-amazon-ads-and-data-leaks
As there won't be a GUI installed and don't think that Linx/lynx would be passing back advertising information to Canonical.