Sebastian brings up a good point - one we've both discussed and I agree with - Conference Fatigue has set in for both Webmasterworld and Search Engine Strategies - the content from year to year is close to 95% the same thing - is the 5% that's new make it worth attending? 

Probably not any longer.   According to Webanalyticsbook.com:

"…I was just reading a bunch of posts with the summaries of the Pubcon sessions and I am pretty sure that besides networking (and meeting friends), I haven’t missed anything.

I wonder why the same people are always on the stage giving the same speeches over and over again.  And not only for one, two conferences, but year after year.

I’ve noticed that a lot of people are very disappointed with conferences like Pubcon Pubcon.