Content publishing: Weekend project. Rails, memcached and CloudFront and you're done.
IM and Buddy Lists: 1.5 million simultaneous users doing n^2 pub/sub-type distributed transactions.
Mail: 4,000 emails per second with live unsend and recipient read/unread status. I think PostgreSQL tops out in the millions of rows per second nowadays.
Web caching/acceleration: pick your favorite proxy solution and configure it.
Single sign-on: Form strategic partn-- Hey, you said technical challenge, not political.
Content publishing: Weekend project. Rails, memcached and CloudFront and you're done.
IM and Buddy Lists: 1.5 million simultaneous users doing n^2 pub/sub-type distributed transactions.
Mail: 4,000 emails per second with live unsend and recipient read/unread status. I think PostgreSQL tops out in the millions of rows per second nowadays.
Web caching/acceleration: pick your favorite proxy solution and configure it.
Single sign-on: Form strategic partn-- Hey, you said technical challenge, not political.