I've found that phone calls are good when people ignore or are bad at reading email (miss questions, fail to respond/read, don't read it completely, etc). For

I've found that phone calls are good when people ignore or are bad at reading email (miss questions, fail to respond/read, don't read it completely, etc). For people who are good at email, phone calls are good (or the same as IM) when you need an in-depth back and forth conversation, for example, discussing some software bug.