Why is Lion downloaded from Facebook servers? (imageshack.us)

One would presume because they both use the same CDN, Akamai, leading to all of their content looking to share a few IP addresses.

$ dig static.ak.connect.facebook.com

; <<>> DiG 9.7.3 <<>> static.ak.connect.facebook.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45796 ;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 9, ADDITIONAL: 9

;; QUESTION SECTION: ;static.ak.connect.facebook.com. IN A

;; ANSWER SECTION: static.ak.connect.facebook.com. 858 IN CNAME static.ak.connect.facebook.com.edgesuite.net. static.ak.connect.facebook.com.edgesuite.net. 9684 IN CNAME a1875.g.akamai.net. a1875.g.akamai.net. 20 IN A 69.64.227.14