There is nothing new when it comes to microservices and there are tons of literature - ranging it from precise definitions stated by Martin Fowler, to the loosely coupled architectural term.
It is also easy to confuse microservice with SOA as the design seems similar; however, SOA is an integration of different applications, but microservices remain independent to each other - you can simply plug in and out different services while using them across different applications.
A) Scale very wellThe individual service can scale up easily - as its underlying micro-architecture contains the least surprises and given today's virtualized/cloud environments, such services can be increased in volume as well as tested and rectified if something goes wrong.
B) StandaloneThe services are standalone in the sense that each application that uses a microservices can use it with a specific set of data and as applications interact over http, there are no hassles of contract based services over SOAP/REST based services, which were based on service contract and were the norm earlier. So, we do not need an elaborate contract or some specific tool ; just a miniature web application framework would do.
An example of microservices making waves is into the SAP Hybris ecosystem via the YAAS that serves both as a place to host as well as market individual microservices for different e-Commerce implementations. Hosting is important because of the sensitive nature of data of different clients (which can be stored as different tenants) and also to remove the complexity of managing the server load when there are a lot more things to be completed.
Creating standalone applications and utilizing their mashup is no longer a field dominated by selected few, but are quickly becoming the norm in the coming time and is poised to become the disruptive force of the decade.