What technical issues are solved by storing DNS data in the main block chain, as opposed to an alternate yet connected block chain, as Mike has proposed?
Incentives. If I want to make an alternative chain for timestamping documents, then no one will ever generate blocks on that chain, since there would be no profit.
If you can easily work incentives into your project, a side chain is better. Then you can do simple payment verification for your chain, too.
theymos, for your consideration:
i think incentives can easily be worked into [mike]'s scheme, if you just change the protocol to require the 'parking' transaction to have X fees. et voila, we have incentives. what do you think?