what do pin numbers for ram stand for

[new.puree]

I am looking around for a stick of 512 ram and i found this
http://www.newegg.com/Product/Product.asp?Item=N82E16820145024

I was wondering what 184-Pin means

 

[AnhZors]

184 = DDR
240 = DDr2

you need to check your slot.

 

[FghtinIrshNvrDi]

It's the size. You've gotta buy the clothes that fit!

Ryan