Usability blogger, John S. Rhodes writes in Apogee that Direct Marketing and UX are the same, or at least share common goals and methodologies. This quote sums up these parallel ways of thinking and working:

There is a serious emphasis on testing and measurement. Metrics are the law. Success is based on tangible results: number of phone calls, number of and type of brochures requested, number of email address captured, number of comments made, number of web page views and so on.

In this way, usability and UX share commonality with direct marketing. We've known for years that we cannot take action on behalf of users without first having data. Educated opinions are useful, e.g., heuristic analysis, but nothing is as powerful and useful as data from research in the lab or the wild.

I would wholeheartedly agree that we could share lessons learned between these 2 fields. In the past year I stumbled on and have taken an interest in direct marketing, mostly due to finding Dan Kennedy serendipitously and reading a book of his. I held the same belief when reading a Kennedy book--we're interested in the same things, with different needs or problems in mind. I'll be keeping an eye out for more on this theme and am sure to blog what I find here.