I know that the wave dash `〜` can be used in place of the long vowel marker `ー` sometimes, but I'm not exactly sure what the differences are.

* Is there any difference in pronunciation? I [read once](https://stackoverflow.com/questions/14450187/having-trouble-with-japanese-character-in-android#comment20124013_14450306) that it represents a "tremolo", but I'm not sure if that's right.
* When is it appropriate? According to [Wikipedia](http://en.wikipedia.org/wiki/Japanese_punctuation#Wave_dash), it's "usually for comic or cute effect". Is that a fair summary?