I had a requirement to return the thread with the most replies in each forum at JavaRanch‘s Coderanch forums.  In Postgresql 8.4, this would be very easy – just use the window functions.  Unfortunately, we aren’t on Postgresql 8.4 yet.  The other common pattern is something like This doesn’t work well for me either because [...]

I’ve always been concerned about the whole “give us your e-mail password and we will tell you which of your friends are registered on our service” thing on social networking sites.  To the point that I refuse to give out the password.  If I give out my password, the sites can do whatever they want [...]