A little while ago, IU added the feature of automatically creating CMRs from SVN commits when you add tokens like this in your commit message:
svn ci -m "This fixes ...foo... cmr:v1.4.2"
IU just extended this feature by allowing you to specify a reviewer, thusly:
svn ci -m "This fixes ...foo... cmr:v1.4.2:reviewer=jsquyres"
You must specify a valid Trac ID. If you do this, the ticket will be assigned to that ID, meaning that they'll get an email with the ticket and a request to review it.
More description is here: