Learn English – When are “from” and “by” interchangeable

prepositionsword-choice

Today I listened to a performance by Stephen Lynch in which he said "A public service anouncement from Stephen Lynch" which confused me, a non-native English speaker. Is the usage of "from" correct here? When can I use "from" instead of "by"?

Best Answer

Either is possible, with slightly different meaning: the origin (from) or the immediate channel announcing it (by).

Because he himself is speaking it, you might expect by. But here it is a joke based on the common pattern A public service announcement from ... where from is used I think because the announcement may have been transmitted through various channels, but its origin is what matters, rather than the particular agency announcing it.