A quick tip for North American readers....

... if you represent a vendor (or 3rd party agency) and you want to convey relevance and understanding of the global telecom marketplace, you might want to consider putting an international dialling code in your email footers.

It's a small thing, but just putting 123 456 789 reduces your credibility and makes a company look really parochial, compared to +1 123 456 789.