6.0 egr valve

alright guys, im about to take the plunge into the diesel world. been wanting to do it forever and within the next 2 weeks i will be a driving a 05-07 ford f250. i have been doing a ton of research on the 7.3 and 6.0 and the biggest question i have is about the egr valve in the 6.0's. i see they are always plugging up or going bad and some people are even deleteing them all together. forgive me for being stupid but i know next to nothing about diesel engines. what is an egr valve and what does it do. also is there a benefit or is it really reccomended to just delete it completely?..any help would be greatly appreciated, thanx :thumbsup: