Question: I am a product/project manager for a product we've created. We have customers using the product, which we are continually updating as it is Web based.

What are some tools and techniques for managing communications with clients regarding product updates?

Answer: 
If the updates to the product affects the customer's ability to use the web application, I will encourage you to use your time of less traffic and to give ample notice. 

If you are only thinking of the actual strategy of communicating the updates, I will suggest the following:

1. Create a YouTube campaign with videos explaining the benefit of each update. This will help educate your users as you tell them the good news.
2. Create a webminar type seminar were you will show users that subscribe the new updates. This might seem like an overkill, but you will get questions from the users that you did not think.
3. Send twitter messages that encourage people to take action, update your profile before the update, etc. you get the idea. This will let you know how effective is that medium.

You need to send similar messages from different sources.
If your updates are small and can be made public, I would include Twitter in your list. Take [the Twitter stream for OmniFocus](http://twitter.com/#!/OmniFocus), [or for FreshBooks](http://twitter.com/#!/FreshBooks) as examples.