Prepositions – Is It Correct to Say ‘Talking to Skype’?

A phrase using the verb "to ban" with a subject and a location typically follows the form "To ban subject from [(verb)ing at] location"

ILLOGICAL: There’s no necessity to ban prepositions from using (them) at the end of sentences.

When you ban something from (verb)ing at location, you prohibit the subject from performing the action at the specified place. Here you are prohibiting the prepositions themselves from using (something unspecified: them) at the location the end of the sentence. The issue here is less the structure of the sentence than the choice of verb: 'using' appears to have no object, and it seems unlikely that a preposition would be able to 'use' (take illegal drugs) in a colloquial sense.

CORRECT: There’s no necessity to ban prepositions from being at the end of sentences.

Here, prepositions are prohibited from performing the action, being, when at the end of sentences. They are not allowed to exist at the end of sentences. This is quite clear.

ALSO CORRECT: There’s no necessity to ban prepositions from the end of sentences.

When banning someone/something, the "verb + at" is optional. If excluded, as in "To ban subject from location, "being in" or "being at" is implicitly understood. This example has the same meaning as the previous example and is also very clearly phrased.

Both correct examples are fairly standard and including "being at" shouldn't sound particularly strange to a native ear. Since language tends towards simplicity, however, the exclusion of the verb is more likely.

The following informal mini-conversation occurs regularly in English:

I'd like to talk to you.
-- About what?

Any grammatical rule that would simply preclude the use of "About what" is a prescriptive rule. A descriptive rule would say, "The idiomatic way to tell someone, rather impatiently and brusquely, that they are not making themselves clear, is to ask What are you talking about?"

About what are you speaking? is "incorrect" insofar as it departs from idiomatic usage. Do you understand how that could be considered a far greater infraction than a violation of some prescriptive rule that has no basis in the spoken tongue?