It is easy to see how Roadify could be useful. But it is the kind of service that gets better as more people sign up, and it has not reached critical mass. It is not uncommon to click on, say, the E train at Queens Plaza, only to find an update saying the station is crowded — from six hours earlier. There is also some development work to be done: More than 20 bus lines have yet to be entered into the database, meaning that if you live in many parts of Queens, you’re out of luck. And the subway information is arranged by line, not by station. Trying to decide which train to take from Times Square? You have to check each line individually. Roadify is also largely nonfunctional underground, a serious shortcoming for something you want to use on the subway.

Why is my iPhone logging my location? The iPhone is not logging your location. Rather, it’s maintaining a database of Wi-Fi hotspots and cell towers around your current location, some of which may be located more than one hundred miles away from your iPhone, to help your iPhone rapidly and accurately calculate its location when requested.

But critics say online education is really driven by a desire to spend less on teachers and buildings, especially as state and local budget crises force deep cuts to education. They note that there is no sound research showing that online courses at the K-12 level are comparable to face-to-face learning.