Well, I've heard that spammers of this kind have no incentive to nail the details... They don't want responses from smart people.

I know in the bottom of my heart I could have been a really good psychic.

Damn my ethics.

Crid is correct. The obvious errors act as a filter - anyone dumb enough to overlook them is dumb enough to fall for fall for anything. This is, of course, more true of 419 scams than of password harvesting attacks, but there's a degree of crossover - people who fall for one get put on sucker lists that are sold to others.

Yeah, anyone who falls for one of these things at this late date has to be pretty slow on the uptake. That said, a lot of these Nigerian scammers don't know that their spam is full of misspellings because they don't read or write English -- they just pass around copypasta. Someone sends them something that they claim worked, so they use it.

Come on, they got the whole first sentence right! Just another example of the spelling police trying to keep a hardworking criminal down.

By the way, I'm talking about the paragraph, not the header.

I suspect a lot of these criminals are either non-English speakers (as Cousin Dave says) or just poorly educated / dumb ... these are people who honestly don't realize there is even a difference between e.g. "sincerely." and "sincerely .", and it's beyond their imagination to think other people would notice such details.

Due to the nature of criminal enterprise it's probably also not that easy to hire a professional English proofreader if you're e.g. sitting in places like Nigeria or Russia and don't want to give the game away ... you can't just call up a professional proofreader and say, "hey, we're busy scamming people, please help"

No matter how amateurish, I always forward such messages to the anti-phishing authorities. It only takes a couple of seconds and I figure I am doing my bit to stop phishing and perhaps catch the perpetrators.

Forward the message -- as an attachment, so they get all the header information -- to the Anti-Phishing Working Group (http://www.antiphishing.org) at reportphishing@apwg.org. You can also forward it to the Federal Trade Commission at spam@uce.gov. And you can forward it the Department of Homeland Security at phishing-report@us-cert.gov. I keep those addresses in my Contacts list for ready reference.

Also, most vendors have email addresses to which you can forward phishes purporting to be from them. Perhaps more than anyone they want to stamp out such phony emails. In the case of PayPal, you can forward the phish to spoof@paypal.com.

Huge numbers of really comical grammatical mistakes, and spelling errors on signs translated into English in Japan.

Their writing system is so different from ours, that most of the details of written English escape them.

It is not because they are stupid. They are not.

It is purposeful. They want to screen out everyone but idiots. An explanation..............
http://crackletech.blogspot.com/2012/05/why-are-e-mail-scams-written-in-broken.html

If you really want to understand this, try writing an error-free scam letter in Russian.

Reminds me of a criminal I heard about years ago who stole a prescription pad from a clinic. He got busted in a pharmacy for trying to fill a prescription he wrote himself that said, "Mofeen 1 pound".