Ok, so at the beginning of my second summer I have an almost-finished obsidian block wall around a fairly large area including a large magma vent, which I have used to make a moat of firey doom. It will eventually become the greatest goblin castle ever.
My findings:
# Goblins are carnivorous. This I did not know. They will starve to death rather than eat vegetables. This is causing serious problems, because I have practically no source of meat. When I worked this out I trapped some groundhogs to breed, but this is hardly an ideal solution because the pups take a while to grow up, and grown groundhogs give a measly 2 meat when slaughtered. Goblins do, however, eat bones, and not just when they're starving, either. I haven't yet worked out if this actually provides nourishment for them, or if it's just something they do for a lark. If the former, that'll help with food issues a lot, but it will make it difficult to provide bone bolts.
# Dwarves are pansies. Goblins are hardcore. When they see a kobold thief, they don't run away like cowardly dwarves, they charge it en masse and kick the hell out of it.
# When you have a nicely dug out fortress to hide in, kobold archer bands are not a problem. When your only defence is your not-yet completed obsidian block wall, you may be in trouble. 3 goblins got shot to death, the rest of the population got conscripted, and charged and beat the kobolds to death barehanded.
# Bringing two proficient masons means you can put block walls up pretty quickly.
# Elves will trade with goblins. Who knew?