We're excited to announce a batch of improvements to private messages, to-do lists, and files in Basecamp. Now it is more clear when you've made an item private and easier than ever to see who can view it. We know private items are important so it's vital that you get clear visual feedback when you mark something "private". When creating a message, a to-do list, or uploading a file, clicking the private checkbox will turn the entire message form light red.
Here is a message that has been marked private. The message box has turned light red and the only parties who will be able to view it are listed:

Once saved, the private flag that appears next to private messages, to-do lists, and files now shows you exactly who can view the item when you place your mouse over it.

Pro tip: You may have noticed that more than one company can view the private message in the example above. The default is to share private items only with your company but did you know that you can choose additional companies to see your private messages? This is great for collaborating with a sub-contractor or partner company on a client project. To allow another company to see private messages, visit the "All people" tab from Basecamp's dashboard and edit the company. Click the checkbox shown below to let that company see your private messages.

We hope you like the ways we've improved handing of private messages, to-do lists and files. Thanks for using Basecamp!