'for texting' is a prepositional phrase with the preposition 'for' and the object 'texting'. It takes a noun to be an object. 'Texting' is the name of an activity. Names are nouns. Note that I am talking about usage. As another poster stated, the word 'texting' has the form of a gerund which is a form derived from a verb that can be used as a noun. It can also be a verb. I am texting him a message right now. Some day that form may be recognized by the dictionary. Dictionaries don't establish language; they describe it according to accepted usage.
English is such a fun language. We can verbify nouns and subject verbs to nounification. Pretty soon, I predict there will one day be only one part of speech, the Interjection.
Wow!
If A = B and B = C, then A = C, except where void or prohibited by law. -- Roy Santoro