store SEO

Now i m setting up multi store as city
say cityone.store,com , citytwo.store.com, citythree.store.com
Now as by default in multi store will create sitemap,contact page etc for each store, what will be the seo effect ?

All sites/stores will be viewed as indepentent (different) sites by search engine. so you need to watch out for duplicate content on the sites (same products/text etc) which might be picked up by google and dilute rankings. Your seo efforts (backlinks/onssite) will need be duplicated per store. Also watch things like meta data which will be duplicated. So - its really powerful, you just need a strategy. -> there are plenty extensions that help you manage all this.