Fueling... the Blockmaker. And the Fuelmaker. Not a whole hell of a lot, currently.
I should add that the blocks, while they are used for street projects, aren't used as heavily as you might think... there always seems to be a massive surplus vs what the project actually calls for. It's a bit of a dead end at the moment.
Djabrill: really? My memory from long street projects in beta was that they would often grind to a halt as we waited for someone to set up a local blockmaker while everyone else was off frantically digging for loam.
Mind you, I think there were longer waits for barnacles, and I wasn't as active on projects as some here (I never did get in a top three, not that I remember).
@blech - My memory for the ones I participated in was that there were loads of blocks bcz everybody with Blockmaking assumed there would be a shortage; turned out that there was generally a longage... maybe these were earlier projects though, I guess.