Guest Blogging is when you write a blog on someone else’s site as a temporary author.
This is a technique used to try and improve the authors reputation and increase their following.
The idea behind it is when you start a blog it can be hard to get people to read it unless they specifically search for you. Therefore, some people choose to offer posts to other blogs that already have a large following.
This is so they can then post that blog on their site for all their followers to see. Which will then increase your exposer and increase the chances of people reading your future blogs.
This is a great form of marketing because you can choose as site that talks about similar topics so you can be certain their followers are your target audience. Some people allow guest blogging for free, while others sometimes charge. Either way it is great exposer to an audience that is likely to like your content.