I just picked up this tidbit from Cameron Reilly's blog about eBay using Microsoft technology. Keen observers will note that eBay appears to have been running with Microsoft technologies for quite some time (ISAPI).

A few years ago now IBM was making alot of fuss about how eBay had chosen WebSphere as their technology moving forward. At the time I was skeptical whether they would be able to get it to scale (factoring $$$ into the equation as well).

I don't know how far it went. eBay still has a "powered by IBM" glyph on their pages but the front end application is clearly ISAPI (look at those MFC give aways in the URL), or some fairly well constructed vanity URLs. Maybe they have WebSphere on the backend with Tivoli restarting it every time it falls over. Question is, what is watching Tivoli? Tivoli is the best piece of "consultantware" I have seen.