I like Adam. I honestly think that his articles are amongst the best on the site, and his anticipation for Spore is shared by millions worldwide. Unfortunately, I feel the article was quite short in all, and left a lot of speculation open without any real analysis. For instance:
How exactly do species transition from one arena of scale to the next, for example?
We know that we use DNA points to add more stuff to our creatures. We get these points based on the period of life we're living (cells, for instance, eat other cells whilst tribes conquer other civilisations). I imagine transition will be slow, but upon reaching a certain stage of evolution, you'll transfer through the stages Sims 2-style.
How large is the universe that I can personally explore?
About a galaxy wide; few hundred planets.
How will content be shared from one user to the next?
Automatic Sporepedia downloads, mainly. This goes for vehicles and building design too.