Anthony from DNSimple here. We've definitely seen a lot more of these messages since the SOPA announcement just before Christmas. Prior to that I almost never saw domains stalled because of problems getting at whois data. Whether GoDaddy is doing it on purpose or if they are just overwhelmed with the number of domains that are being transferred out is pure speculation at this point.
In the case of DNSimple, if you get a message like that we are currently recommending that you email us (support@dnsimple.com) and let us know which domains are currently responding with that message and we'll cancel them so you can try them again. It's a brute force way of dealing with it, it's inelegant and may end up causing even more problems for GoDaddy, but we have found that has helped a bit.
To be certain, this is different than the 5 day waiting period that ICANN allows. That only comes into effect after you've submitted the transfer request to the registry, and if you haven't received an email to authorize the transfer request then you aren't at that point yet.
Can you say a little about what it would mean for Whois to be "overwhelmed"? We're used to hearing about sites going down dealing with hundreds or thousands of requests per second, and as much as we'd all like to see GoDaddy collapse into rubble their transfers are probably more on the order of thousands a day.
How plausible is it that they could actually be seeing technical difficulties?
I agree that it seems unlikely that the whois server is having technical difficulties, rather they are probably throttling requests. Consider that spammers use whois servers as a means for harvesting email addresses and therefore they are likely limiting requests from specific IP addresses.
On the other hand, if I were a relatively large registrar I'd figure that I should have a mechanism for getting whitelisted at other major registrars, so I find it hard to believe that this issue should not already be resolved, although clearly it has not.
Interestingly enough, not long after a number of "blocked" customers (including myself) submitted complaints to ICANN about all this tomfoolery, GoDaddy contacted NameCheap and let them know that the blocking was all taken care of. Also, my stuck transfers suddenly unstuck.
We can all speculate about whether this was malice, incompetence, or just plain old DDOS protection working as designed. Either way, it looks like the squeaky wheel got the grease.
I would imagine that because just as they need to have the ability to transfer out, they also need to transfer in. It would make sense to whitelist in the event that there is an overwhelmingly large amount of transferring in.
In the case of DNSimple, if you get a message like that we are currently recommending that you email us (support@dnsimple.com) and let us know which domains are currently responding with that message and we'll cancel them so you can try them again. It's a brute force way of dealing with it, it's inelegant and may end up causing even more problems for GoDaddy, but we have found that has helped a bit.
To be certain, this is different than the 5 day waiting period that ICANN allows. That only comes into effect after you've submitted the transfer request to the registry, and if you haven't received an email to authorize the transfer request then you aren't at that point yet.