Not exactly. He's not performing
Blynk.virtualWrites() so he not flooding anything. His arduino hardware will be happy enough performing an ADC read and map() in the loop.
The issue is he is relying on the app to read the hardware determined in the widget settings in the app. The INTERVAL time. Default is usually 1 second.
This is okay... but its kinda slack and only works while the app is open. So only good to play with.
@markop, you need to use some virtualpins. Copy the PushData.ino Example (also in your IDE menu). Set it up on your network, with your auth code etc and get it working.
Then change the widget to a gauge.
Then change this part of the code from this:
Blynk.virtualWrite(V5, millis() / 1000);
Blynk.virtualWrite(V5, analogRead(A0) );
Or just add a new line and change the V5 to V6 etc... then have both (why not eh).
This will update the gauge every 1 sec on the HARDWARE side.... far more reliable.
Work from this example from now on and you will be okay.
Leave loop() as it is. Just the 2 lines.
This topic by @Costas is a great place to start! http://community.blynk.cc/t/blynk-for-beginners/10000