OK, you can't do this directly. But you can do the next best thing! Use the Community Content feature in the MSDN Library to add more information, examples, clarifications, or corrections for all to see.
Let's take a look at this Integration Services page in SQL Server 2008 Books Online as an example (link opens in a new window): Configuring the Integration Services Service.
To read community content:
1. At the top of the article, observe the Community Content box at the upper right. For this BOL topic, you see that it already has 1 annotation.
2. If you "expand" this box by clicking the link, you see information about the existing notes and their contributors:
3. To view the community content, either scroll to the bottom of the page or jump there automatically by clicking the Community icon on the toolbar at the top of the topic.
In the Community Content section for the Configuring the Integration Services Service topic, you'll see (see next image) that the contributor has pointed out that trying to use the ServerName\InstanceName syntax to refer to the default instance of SQL Server running on a cluster node doesn't work.
To add your own community content:
1. If you want to ADD a note, you click the Add new content link:
2. Then sign in with your Windows Live ID. (In other words, anonymous comments are not supported.)
We're happy to have all of you as our collaborators!