I know it's the affiliate account. I just received a paycheck from Google, not HubPages, didn't I?
Think about it, though. All writing for journals, newspapers, magazines, gets most of their money through the advertising that accompanies GOOD writing. True, you can get an eye to catch your ad even if you don't write well. But most people are fired from the newspaper staff if they don't write well, because bad writing brings fewer readers which means less people to see advertisements, which in the long run means less advertisers pay to appear in the newspaper. It's the same with HubPages, only the connection between advertiser and writer is a little more direct. People don't spend a long time on a page that is hard to read because it's poorly written. Hence, you have less chance that they'll click on an ad.