Point taken - what I primarily wanted to show is that the correct way is not much longer than the "looks like" solution. Yes, the Regexp is long, but it is nicely encapsulated in the Email::Valid module.
Yeah - I've read only the first sentence. I think many of those that will find that article from google and even use that code will also not pay much attention to that weak disclaimer. Also these were not the only problems with his code - see the comments at that page (in particular: http://www.catonmat.net/c/35784).
But the more important point is that an article that sounds so authoritative should present much higher quality.
But I doubt someone new to regexps would understand what "looks like" means in that context. For instance they might think "ok, so something like 'abc@efg.xyz' matches, even though it's not a real email address." They might not think to consider that a full sentence like "hey, I'll see you tomorrow @ 2. Can't wait!" also matches.
That said, perl one-liners are certainly useful so thanks to the OP for putting this together. I just think it would add a lot of value to include examples of where one is likely to go wrong.
`Notice that I say "looks like". It doesn't guarantee it is an email address.`
And yeah, you can find the full regular expression in the back of one of O'Reilly's Perl books (the regular expression handbook I believe).
It's nice to see perl code from time to time, even if it's just one line :)