Wow, it was big! I think it affected me, but not terribly. I'm thinking Russia didn't push this attack, because it's the kind of attack we can probably fix over time with smarter, more locally distributable DNS caching. But for a while it could get worse!
Sometimes it never finishes loading the whole page, although it might visually look complete. It seems the code that enables replies comes last, causing symptoms such as no font or formatting buttons, or worse, the code arrives after you've started writing the reply, and then when you hit the Add Reply button only the first character of what you wrote gets posted.
I've noticed this happen more frequently than before, especially on a mobile connection, but I thought maybe it was because I've been on a slow mobile connection so frequently, recently. I got used to watching the top of my browser for how fast the page loads, and if it completes in a reasonable time. I'm in the habit now of copying my entire post to the clipboard as I'm writing it, which has saved me a few times.
I'm not familiar with other Ning sites, and have rarely seen the 500 error, bbut that might depend on which browser we're using. Another problem I encounter is failure to use https protocol (often flagged as an errant or missing "certificate"), so i have to change the https in the URL at the top of the browser to http, without the s.
I'm guessing these problems also happen more often when Ning sites are the busiest, meaning they're not as robust as they should be. Probably a money and/or quality failure issue. (So here I go again, on mobile, selecting all text and copying it to the clipboard before clicking the Add Reply button, in case it fails again...)
I will add that using a portable bluetooth keyboard has greatly reduced my frustrations on mobile, even when not encountering the above problems. I should also add that sometimes reloading the whole page works faster than waiting for a slow load to finish.
The 500 errors have plagued Atheist Nexus all year off and on, sometimes lasting for days. I don't know what the issue is. I've seen it on other Atheist sites but my impression is it also affects other Ning sites. Somewhere in my mind is the possibly-true information that Ning has been sold, so maybe there are factors there as well.