This possessive plural pronoun references a group of which the speaker is a part as in our house, which is a house owned by the speaker and others. There is no limit to the size of the speaker's group. Our can refer to a group as small as two as in our song or to all of humanity as in our universe.
In formal speech or edited writing, gerunds (verbs ending in –ing which function as nouns) are proceeded by the possessive form of the pronoun or noun (my; your; her; his; its; our; their; child's; author's) rather than by the objective forms (me; you; him; her; it; us; them): The landlord objected to our (not us) having guests late at night. Several readers were delighted at the author's (not author) taking a stand on the issue. In standard practice, however, both objective and possessive forms appear before gerunds. The occurrence of objective forms is increasing; in informal writing and speech objective forms are more common: Many objections have been raised to the government (or government's) allowing lumbering in national parks. Does anyone object to us (or our) reading this report aloud?