This is a simple tricks that should be working properly to remove Ads aka Advertisement of Yahoo Messenger 9 in Windows Vista. This tricks need an administrator of Windows Vista User.
First go to Folder Options in Windows Explorer: Open My Computer >> Organize >> Folder and Search Options. Then on View Tab, un-ceck the “Hide protected operating system files (Recommended)”. Note: sometimes this steps not needed.
Go to Start Program >> All Programs >> Accessories >> and right click on Notepad >> Run as administrator >> windows notification appears click “continue”
On the window of notepad application, click File >> Open
Then open the hosts file on the c:\Windows\System32\drivers\etc\hosts . You should see hosts file in notepad open like this:

Then add one line on the hosts file with
127.0.0.1 insider.msg.yahoo.com
The hosts file should be like this:
Save the file by click on the notepad tap: File >> SaveThat woulds make the Ads in Yahoo Messenger 9 on your Windows Vista disable (Remove and disappears). See the Removed Ads Screen Shot Below:

The Ads that would be disappeared: Banner Ads on Webcam, Banner Ads on Login to Chat Room, Chat Room Ads, and also the Main Windows of Yahoo Messenger 9 Advisement Banner.
Note: this tricks could make you YM plugin error and others features of Yahoo Messenger not working (such as loading chat room list).
If you wanna use chat room, just simply add favorite chat room before you add line on your file hosts and then you can join by clicking favorite room. If you wanna change the room just type /join canada:2 or other available chat room.
Suggestion from mr legman
Add in your file hosts with this line:
127.0.0.0 chat.yahoo.com
Tags: Tips and Tricks, Tutorial, Yahoo! Messenger
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May 21st, 2009 at 12:57 am
NOTHING
May 21st, 2009 at 12:59 am
I LIKE THIS MESSENGER CAN GIVE ME
June 9th, 2009 at 7:29 am
Hi everyone. For the new messenger i saw that non of old methods are working. I have a website with some downloads. http://baiamare.myftp.org/downloads.php?cat_id=13 here you can find yahoo messenger with a patch that is working. ;) good luck!
July 15th, 2009 at 5:11 am
you cant block insider.msg.yahoo.com if you want to get in a chat room.. insider.msg.yahoo.com is also used to get the room list. if you want to get rid of the ads in the chat rooms. block chat.yahoo.com. add 127.0.0.0 chat.yahoo.com to your host file.. if you look your yahoo cache folder youll see urls.xml in there youll see
thats the url yahoo uses for the chat room ads.just block it. this works on the new messenger.i tried all the reg changes and other tips posted on the web none of them worked for the new messenger so i had to find my own way.
127.0.0.1 insider.msg.yahoo.com works good if you dont use the chat rooms
July 16th, 2009 at 2:42 am
@legman: where is the yahoo cache folder? I can’t find it.
July 22nd, 2009 at 7:10 pm
C:\Program Files\Yahoo!\Messenger\Cache
May 21st, 2010 at 7:52 am
Hi, can you tell me how can i block yahoo chat rooms from my yahoo messenger.
May 22nd, 2010 at 3:56 am
http://www.messengeroo.com/yahoo-messenger/tips-tricks/block-access-to-yahoo-messenger-chat-room-child-protection/