In one of the recent discussions, a member said, "I just spent a week at home, and don't want to waste this posting–hence the bump".
What does the boldfaced part mean?
His first post had not been answered for a long time. By adding a new post he bumped the topic up to the top of the updated topics list. This again brought it to our attention and someone (Grant?) responded.
And (to answer the other part) he felt that if no one replied to the post, it would have been wasted, ie effort expended with no benefit.