The passive voice is a great way to hide critical information:

• This sentence was written yesterday. (But I have no idea who wrote it.)

The message can be even more abbreviated and obtuse:

• This sentence was written. (But by whom, when, and ....?

Even if we include the missing information, the emphasis is deflected from the issue of who wrote the sentence because the subject of the sentence (the focus of attention) is not "who the author is". The author (the doer) is almost parenthetical information.

• This sentence was written yesterday by one of my technical people.
• This sentence was written yesterday (by one of my technical people).

No wonder that people like to use the passive voice when writing reports; they can completely avoid identifying who is responsible for a situation!

• The failure in the bridge supports was due to the fact that the bridge had not been regularly inspected.
  
  But the reader probably wants to know who caused the problem:
  
  
• The failure...had not been regularly maintained by J.B. Cochrane. (still passive voice)
  
  preferably stated this way:
  
  
• J.B Cochrane did not regularly inspect the bridge supports, so they failed.

The passive voice also sounds more formal, because it implies objectivity. (Nobody is involved.) This is why the passive voice is almost always used for experiments, studies, and technical information. It sounds so perfectly scientific to say:

• The solution should be kept stirred while the dry ingredients are added.
  
  instead of:
  
  
• You should continue to stir the solution while you add the dry ingredients.

Compare our original sentence, now written in the active voice:

• One of my technical people wrote this sentence yesterday.
  
  with its passive voice version:
  
  
• This sentence was written yesterday.

Does it sound more sincere? Using the active voice usually produces a sense that the message is direct (to-the-point), people are an important part of the "equation", the action is more dynamic, there is more immediacy (happening now), and in general, that the message is more sincere.

(The active voice also tends to produce a more forceful tone, but that is a topic for another time.)

A bonus of using the active voice is (most often) a more concise sentence, because it eliminates some use of the verb "be" and often a preposition.

• The message should be listened to by everyone.
  (passive - 8 words)
• Everyone should listen to the message.
  (active - 6 words)

You are probably thinking that I don't like the passive voice at all.

For business communication, the active voice is usually the better choice, and should dominate. After all, business communication is mostly about people doing things with each other, building trust, and being efficient.

Passive voice can be used to add variety, and is sometimes more appropriate to the communication task. (Who is the reader; what is the purpose?)

But it's easy to be mislead about which voice to use. For example, of the following two choices, the passive version seems to be the best. Who cares about any person being mentioned in this situation?

• You should put tab A in slot B. (active)
• Tab A should be put in slot B. (passive)

Surprise! There is yet a better choice, and once again it is active:

• Tab A fits into slot B. (Thanks to Deena Madnick for this version.)

I'll repeat: the writer has to consider the reader and the purpose of the message, and either personalize (typically) or depersonalize and formalize (infrequently) as required.

To keep it simple, use active voice whenever possible in business communication, but consider the occasion (the message, the reader, and other context).

But if you are writing all these active voice sentences and you find the tone is inappropriate, (too chummy or possibly too forceful) or simply that the sentences lack variety, then change some constructions to the passive voice. A few. Deliberately.

Much more can be said (see, I shifted for variety) but I'll make just one more point:

Many of us still write much too formally for general communication purposes; consequently we shift automatically to the passive voice. We need to consciously steer away from that tendency. We need to adapt to the modern tone of business writing, which is a lot more personal and informal than it was 30 years ago. Old-time writers will find it hard to shake off the passive voice. They don't even feel comfortable using pronouns (too personal). I suggest "get personal." Build credibility. Don't make the words dominate the delivery. Be active. Look the reader "in the eyes". Let the reader perceive the sincerity in your "I's".