looks like the perks are anologous to talent trees like in World of Warcraft (for example). i don't think they're be quite like fallout's perks. look at the screenshot displaying the skills and constellations, each star of which (according to Todd Howard) represents a perk
- each skill has a perk tree associated with it.
look at the screenshot - skills are at the bottom, and destruction is highlighted. above this skill list are stars. there are bright 'baseline' stars, above which are lines connected to other stars. the centre constellation has bright white lines, and behind it is a symbol of hand representing fire - this must be the constellation representing destruction.
- the perk tree has multiple paths, indicating specialization is possible within each skill.
eg conjuration has four lines from the bright baseline star. eg there may be an armor summoning path, an undead path, a daedra path, etc.
- perks requiring multiple skills are possible.
the magic skills in the screenshot are not alphabetical - presumably so displaying perks requiring previously-earned perks from multiple skills is less cluttered. such perks were in fallout, of course
You hit it right on the head there. Looking at the pictures now I can definitely see that, and it was what I was expecting anyways.
In essence, every skill has a deep talent tree system. From counting, it seems like each skill has some 3 perks deep (discounting the first, base perk), and also 4 perks wide (also discounting the base perk), for 12 perks. Add the base perk and that's 13 perks per tree. 13*18 is 234 perks, not including perks that are general or require multiple skills.
DISCLAIMER: THIS IS JUST DEDUCTION, THERE IS NO PROOF THAT MY MATH IS CORRECT EXCEPT A SINGLE SCREENSHOT THAT SEEMS TO FOLLOW MY OBSERVATIONS