SQL Management Studio Shows All Databases
Looks like I'm not the only one. 
Jason N. Gaylord Blogged about something today that has bugged me for a long time.
It's also something I get asked all the time in the DiscountASP.NET forums.
We do our best there to provide helpful answers and solutions while remaining 100% faithful to Microsoft.
From Jason:
SQL Management Studio Shows All Databases
This has "bugged" me for awhile. When you log into any version of SQL (2000, 2005, and even 2008) as a user with restricted access to just a single database (or even a few databases), you can still see a complete list of all the databases on that server. There have been times when I needed to share a database with a customer or have accessed a shared database at a host such as DiscountASP.net or GoDaddy and can see all of the customers on that one box. It's more of a nuisance than a real threat but I really wish it was changed. It has been confirmed as a bug. Please vote for it at http://tinyurl.com/6pk74q
http://weblogs.asp.net/jgaylord/archive/2008/05/21/sql-management-studio-shows-all-databases.aspx
Thanks Jason 
Yes, to everyone on the SQL team at Microsoft...Thanks for all you do.
I started working with SQL Server 7 for ASP commerce back in the late 90's.
Before that I used Borland Paradox for business and Access/Excel at home.
SQL Server 2005 was so vastly improved I started using it at home for just about everything, including Outlook 2007, sweet. 
I can't hand out any secrets but you can rest assured that we will be bringing the best of SQL Server 2008 to DiscountASP.NET
(I'm very excited about that.)
Salute,
Mark Wisecarver
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Salute,
Mark Wisecarver
Technical Evangelist for http://DiscountASP.NET
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