1. List Building
2. Internet Marketing generally?
For me, my list building frustrations stem from all of those "gurus" who tell you that "the money is in the list" and proceed to sell you ways of getting big lists that don't convert. the money is in buyers, pure and simple.
My biggest frustration in Internet Marketing generally are the snakeoil salespeople who sell shiny objects and lull people into failing to realise that internet marketing is a business, same as any other. It took me a lot of wasted time and money to figure that out!
Your turn - what frustrates you?