Recently, one of my colleagues came to me with an issue he was having with SharePoint.  After making sure it wasn't friendly "user error", I determined this to actually be a bug in SharePoint 2010 RTM.  Here's the issue:

On your SharePoint 2010 RTM farm, go to your My Site Profile page, and edit it.  You are able to change the "Activities I am following" once, and save.  But when you do it again, save and double-check, the change was not saved.  What gives?!  

No you're not crazy, and no it's not permissions (for once)!  I believed it to be a bug because Microsoft had admitted it in a technet post, but I just wasn't sure when it got fixed.  After some research, pretty early on actually.  This specific issue was identified and fixed in one of the individual June CU updates, specifically KB983497.  Under issues that are fixed, you will find this statement:

  • You clear an activity that you follow in your edit profile screen. However, this action cannot be undone.

So there it is.  Obviously, you should apply the latest cumulative update available like the good SharePoint admin you are, after taking appropriate backups of course.  The August CU had a ton of good fixes for the User Profile Service Application, and more in December.  Todd Klindt has a great article on slipstreaming these updates into the install source, as its best to have these fixes in place before you create the User Profile Service app.

You can always find the latest and greatest info on CUs at the SharePoint 2010 Update Center

UPDATE 4/13/2011- After applying the Februrary 2011 Cumulative Update, the change now sticks properly.