I just learned a bit about InnoDB. While it seems to provide significant performance advantages and reduce locking issues, it doesn't, in the current stable version, support MySQL/MyISAM's FULLTEXT index. That's the reason Kuro5hin currently only allows 30 day searches. According to InnoDB.com, MySQL 4/InnoDB will support FULLTEXT.
So InnoDB isn't an option for the time being. If we want to get quick improvements, moving the article counters out of the CUR table sounds like a good idea.
PostgreSQL appears to have a module for full text indexing: http://techdocs.postgresql.org/techdocs/fulltextindexing.php
Regards,
Erik