What is Reverse DNS record?

 Reverse DNS lookup is the process to get designated domain name from an IP address.
http://en.wikipedia.org/wiki/Reverse_DNS_lookup

The Guerrilla Guide to Interviewing (version 3.0)

http://www.joelonsoftware.com/articles/GuerrillaInterviewing3.html

The Architecture of StackOverflow

https://speakerdeck.com/sklivvz/the-architecture-of-stackoverflow-developer-conference-2013

45 Useful JavaScript Tips, Tricks and Best Practices

http://flippinawesome.org/2013/12/23/45-useful-javascript-tips-tricks-and-best-practices/

How to solve "Collection was modified; enumeration operation may not execute."?

For IEnumerable collection, need to use ToList first, so you can get same list during the iteration.

                foreach (var qs in one.QuestionSets.ToList())
                {
                    dbc.Questions.DeleteObject(qs.Question);
                }