Whether contact is made by snail mail or email the basic rules of direct marketing continue to apply. The DMA says people like and will read and even pass on, content which is:

1. Relevant – in my book this is about knowing your customer or prospective customer and tailoring your communication to their needs. Why would you be targeting a company with something totally inappropriate, it’s like asking Mrs Lincoln if she enjoyed the play?
2. Interesting – again being interesting is a matter of knowing your audience. The fact that whale’s penis is called a dork is not a lot of interest to people selling orthopaedic mattresses. However beginning with a clear message that is relevant to your reader and their business and saying what you have got say in simple language, clearly, concisely, and succinctly will help to sustain their interest.
3. Timely –umm what does this mean? 1. Occurring at a suitable or opportune time; well-timed. 2. Archaic Coming too early; premature!! Personally unless you have a clear lead, specific marketing information, or topical news timing in serendipitous. Landing on the right desktop at the right time is when you get lucky on more than one occasion I have picked up a great piece of business when the reader had just come out of a meeting tasked with finding exactly we were selling. Although I believe some days are better than others catching someone at the other end in a particularly good mood is definitely helpful and timely.
4. Humorous – you take your chance on this one as not everyone shares the same humour and the written word can cause problems because in print, because jokes often don’t come across the way they do in person and even an innocent cartoon can misfire. Some years ago I sent out a cartoon accompanying a marketing letter, it was a take on Leonardo’s Vitruvian Man. It was very well received by 95% of the targets but offended a handful. To this day still think I could never have done business with the people who took offence. The other pitfall is cultural and national differences how do you know the religious beliefs or nationality of the person reading your email, heaven forbid he might be an Australian.