By being able to query on the subject and date would allow querying on a segment of a mass interaction rather than simply pulling up all mass interactions with a specific subject (or the first and last). Rather than having to create unique subjects for each mass interaction and exporting then manipulating data, I could query on who got a certain mailing between XX date and XX date. We can't always predict how we want to report out - so, placing such importance on subject lines isn't practical. I can't imagine a mass interaction that I wouldn't want to query using subject and date. For example: How many premiums did I send out during XX date range? I send premiums all year long, I'm not sure what dates I'll need to report on...so I can't predict how to word a subject line if I don't know exactly how I'm going to be asked to report on it.