1. Autoblog means, your site will update automatically, content is auto but u still need SEO work manually.
2. Depend what type of auto blog you running.
3. Same like normal site, Advertisement, product or anything related.
For me (most don't agree), Search Engine like google, yahoo, bing and others is world bigger auto site, all content grab by bot and update, what they do is same like most auto blog, just their scrap script is much more advance then any script you can find online , concept is same but tool and marketing make huge different ..