Personalization is a site interface, design or feature that demonstrates to your shoppers that you know their wants or needs in a way that makes them acknowledge that you understand what they want. For example, if shoppers appreciate the ability to organize lists of items that can be categorized, then starting with a feature like Wishlist will help. Giving the ability for shoppers to create unique lists, name them and share them with others through social or email makes your site personal to them because they have vested information or ease already created at your store.
No. Innovation happens when there are special needs, unique products or particular ways for shoppers to buy products. Since the market has not discovered them all, or there are very rare instances of particular "innovations," merchants and agencies will continue to discover new rare ways to do eCommerce.
Some verticals are crowded with hundreds, if not thousands, of competitors while others have found a niche within a category. Innovation helps merchants find a bit of a niche while personalization allows merchants to connect with their shoppers. A combination of the two can sometimes produce an increase in sales. Merchants that gravitate towards selling the same products as every other site with the same expectations and features tend to slip into the status of being the lowest price merchant.