We don't really know much about what goes on inside the Radley house. We do know that Mr. Radley was stabbed by Boo with a pair of scissors one day; and that, like Boo, the Radleys spent most of their time inside. Mrs. Radley was occasionally seen outside watering her flowers, and Mr. Radley made regular trips past the Finch house with a bag of groceries. When Boo's parents died, brother Nathan came from Florida to watch over him, and he proved to be a bit more visible than his parents. Though Boo is never seen, Miss Maudie knew that he's still alive since
"I haven't seen him carried out yet."
The reader also knows that Boo is still kicking, since Scout recalls seeing
... an inside shutter move. Flick. A tiny, almost invisible movement...
And later, she hears a sound coming from the house,
... so low I could not have heard it from the sidewalk. Someone inside the house was laughing.
The Radley Place serves as a place of mystery and foreboding--Maycomb's haunted house--and of sadness. The sense of the unknown that surrounds the house and the mere thought that Boo Radley lives inside frightens children away. As for the inhabitants, they reside in a house where misery existed long before Jem and Scout were born--and a house that died when young Arthur began his confinement inside.
The significance would be that they events led to rumors about Boo and that later made the town afraid of him. The events would be what was said to happen(like that Boo stabbed his father with a pair of scissors)and that his father died.