Wayne West (9/29/2015)
Why are you using NVARCHAR for an email address?
We now have Unicode URLs, so why not Unicode characters for email addresses. You can Google Unicode Email and there's also this Wikipedia article: https://en.wikipedia.org/wiki/International_email
There's some interesting issues that we're going to have to cope with at some point, especially if you're a multi-national org.
It's on the way - possibly - but it isn't here yet. Now bearing in mind that the point of the article was efficiency, I'd still argue in favour of VARCHAR.
I seem to remember back in the '80s some argument about not needing to put the century in date representations - cos it wouldn't happen for a long time.
Dealing with the problem when it comes may well be a case of "Not my Problem", but someone will have to fix it. Software often ends up being used long after its original expected lifetime.
Yes it may be arrogant to assume that one's latest masterwork will still be going in 20 years time, but it seems short sighted to hope that it won't. Way back then, computers were expensive and seriously limited, storage, memory, cpu horsepower, even screen size/capacity were are all major hurdles to overcome. There were significant gains to be made by compressing data - though why people didn't store dates as day counts and convert for display escapes me.
Nowadays we have cloud providers falling over themselves to throw free storage at us. 64-bit memory means that we can size our server to meet the caching needs. The performance hit from nvarchar/nchar can't be that significant. Space to store Unicode should rarely be a problem worth thinking about.
In fact I am bemused that varchar and char are not on the deprecated list. I always use nvarchar unless something indicates that it might need a rethink. Developments nowadays need to consider their likely use across the world and in unexpected ways.