Does the second precept only apply to theft? Considering the second precept


  Adinnādānā veramaṇī sikkhāpadaṃ samādiyāmi.


which I am most familiar with its translation as 


  I undertake the training rule to abstain from taking what is not given


Does this precept only apply to cases of theft or can it be extended into more intangible possessions such as someones time or energy? Considering the answers around the illegal download question it does seem as if there are interpretation in which it is only theft. I'd particularly like to know interpretations from different schools and the differences (or not) between them.

For this can we take the definition of theft as provided by wikipedia


  theft is the taking of another person's property without that
  person's permission or consent with the intent to deprive the rightful
  owner of it.
No, it's meaning is far wider even in Theravada, let alone in Mahayana.

Check out Thanissaro Bhikkhu's compilation of Vinaya: the cases he lists include dealing with counterfeit money and smuggling goods without paying custom duties -- which clearly goes beyond expropriating someone's property. 

Of contemporary teachers, e.g. Bro. Chan Khoon San (trained in Myanmar's Theravada) lists the following Types of Taking What Is Not Given in his Introductory Course on Early Buddhism:


  
  The most blatant, involving threats or force, are daylight  robbery, extortion, purse snatching, kidnapping. 
  The second type is stealing or secretly taking the article without  the owner's knowledge such as housebreaking, burglary and 
  pick-pocketing. 
  The third type is fraud, laying false claims or cheating by  confidence tricksters to gain someone's possessions. 
  The fourth type is deceit when dishonest traders cheat their  customers by false weights and measures or supply products of  lower
  quality than specified. 
  The fifth type is forgery when people pass counterfeit money as  real or sell counterfeit gold and jewelry. 
  The last type, though seemingly slight, is very common and  occurs when employees take small items from their company for  their own use
  without paying for it.
  


Most importantly, we should not forget the main purpose of training rules: to help one "curb the grosser forms of defilements" (Bro. Chan Khoon San): 


  The actions prohibited by the precepts such as killing, stealing,
  sexual misconduct, false speech and  partaking of intoxicants are all
  rooted in greed, hatred and delusion and when we succumb to them, we
  strengthen these evil roots that they become dominant traits. By
  undertaking to observe the precepts, we weaken the grip of these evil
  roots by dispelling them with wholesome mental volitions. Each time
  the precepts are upheld, each time the moral volitions become
  strengthened, until  eventually morality becomes a habitual trait
  through the condition  of repetition (asevana paccaya).


Sat-Dharma (True Dharma) is famously "good in the beginning, good in the middle and good in the end". Among other things this means that Buddhist precepts both play their role at supporting social harmony and decreasing anguish at large, AND they propel the practitioner towards Enlightenment. All interpretation of Buddhist precepts must be made in light of their dual purpose.