Skipping Load Testing is a Dangerous Choice
Every day web developers make the decision that load and stress testing is NOT necessary for their site or application. This is very unfortunate for the website developers. The money they spend for load and stress testing is money well spent. To go to all the trouble to develop a website and not see how it is going to perform is nonsense.
Performance of your site has a direct correlation to your success. Slow sites lose revenue. Sites crash under heavy traffic every day because they got a favorable review on Slashdot. Unexpected volume comes from unlikely sources and blindside your company. Digg, Reddit, Twitter, and hundreds of other social media sites can immediately pour tens of thousands of users to your URL. How will your site handle it?
If you don't load test, you won't know. If you don't measure the performance of your system under large traffic, then you will have no opportunity to tune it to make it more scalable.
If you ignore the facts about load testing, then you will pay the price - some day and some way. I strongly recommend that you run a stress test against your system to see when and where it breaks.
Work with your marketing team to figure out their goals for large volume. Share with them real metrics regarding the number of concurrent users or the requests per second or the throughput that your site can handle. It's not that hard, really!
The hardest part is investing the time. Okay, maybe it's harder to talk to marketing people. It must be done though - even if you don't like it.
Get over your resistance to load testing and just do it. The upside is too important to ignore.
Consider it good insurance.