Hilariously, the massive media frenzy surrounding the site outage will send the site enough traffic to DDOS it, even if LulzSec never meaningfully impacted it in the first place.
This actually serves two purposes:
1) provides some security by sufficiently isolating the actual system from public access (it can be locked down to only serve requests from the CDN)
2) Prevent the type of DDoS described in the parent comment. Akamai is designed to handle the load from things like the Grammies or Superbowl.
For example, it's been documented that the White House uses Akamai extensively.