Please note the following features only work for MSN Messenger 7.0 (Download it at
http://messenger.msn.com/beta/download/downloadx.aspx)
The custom search bar can be used to search on Google or other search engines other than MSN Search Engine. After selecting Yes for that specific feature, type "http://www.google.com/search?q=$QUERY$" without quotes. Then you can go to your Contacts List window, and go to the bottom, type something then click Search and it'll search Google.
To use the Polygram feature you just have to have it selected. After its selected, click OK on the dialog box and now you can open up multiple MSN Messenger Clients. You must have two different emails registerred with MSN to use this feature.
Hope that helps!