Scuze me, thought you were talking about using an external serial EEPROM since you had just mentioned an SD card. Wasn't even thinking of the 328p, that's why I referred to EEPROM datasheets and sizing terminology.
BTW, it really doesn't matter what any Arduino documentation might say about technical specs like current limits. So don't bother citing any of that when talking about electrical characteristics of the 328P. The only thing that matters is what the manufacturer puts in the datasheet. Also, characterizations of "typical" devices can be interesting like many of the charts in the datasheet, but they really can't be used to make design decisions. You have to use worst case numbers if you want to create reliable circuits.
You can argue until you are blue in the face about it being ok to suck 40mA from a pin, and you can come up with all the rationalizatons you can dream up, but you're still wrong when you start advising others to do things that way. You can do things however you like in your designs, but don't expect to post in a technical forum that it's ok to exceed the recommended specs unless you want some flack for it. Honestly, you shouldn't even be drawing over 20mA from any pin. That's why they don't characterize the device for any more current than 20mA at 5V.
EDIT: I see where you got those numbers now, and I understand what you were referring to by them posting it on the web site advertising. All I can see is, they shouldn't be doing that and welcome to the world of marketing. Most of those claims are straight from the absolute maximum section. That's why you should always just download a datasheet and verify any marketing claim that you intend to actually depend upon.
You probably don't care, but heavily loading a pin can have other peculiar side effects. I don't know how much the AVR arch. mirrors the PIC, but trying to read or change the state of a heavily loaded pin can end with erroneous results when it's a RMW (read-modify-write) setup. Just because you can load a pin like that and not fry it is no excuse to do so. You can pull allot of hair before figuring out why other pins are changing state when you try to change one.
I wasn't trying to be a butt to you. You kept asking me questions about what I was saying, so I tried only to answer them the best I could. Just go back and look at the thread.