Terri,
That is dog fennel.
Dog Fennel (Eupatorium capillifolium) If in doubt, run your hands along the stalk growth. If they come away sticky, you can be assured, this is what it is.
As you mentioned, it is easy to pull them out as they are not very deeply rooted. I let some grow in my garden area just to provide some shade from the heat for other plants. But when I do pull them out, they don't come back terribly. It's easier to keep away than goldenrod for sure.
Molly
