Verizon has updated some of their terms this week and those updates, now state that Verizon will use your info for "certain business and marketing reports" and for "making mobile ads you see more relevant." In other words, Verizon will be tracking URLs of websites you visit and also your device's location data while sharing it with outside companies. Doesn't sound all that great does it?
Having the option to opt out is great! Having been opted in by default -- not so great. If you're not down with Verizon doing this, then make sure you opt out as soon as possible.
Source: Computer World