The interviewer may ask the question because they haven't read your resume and know little about you. They may ask the question because they are new to job interviewing and have little idea how to proceed. It may be the job interviewer is stalling for time and wants to see what the candidate has to say before plunging headlong into a series of more probing job related questions.
Either way this question gives you a great opportunity to summarize your job skills. It allows you to demonstrate exactly why you are a perfect fit for the job.
There are two key things that every job hunter wants to do when answering this question. Firstly they want to make this job hunting summary match the job description. Secondly they want to make sure that you appear to be the perfect interview candidate for the job.
It is one of the most common job interview questions so you should have a prepared job summary statement which lists your job skills and personal characteristics.
The job summary statement of any candidate can in fact be created in reverse. The job description will list the required work related skills and experience. Secondly it will also list the personal attributes that you need in order to fulfill the requirements of the job. Use this to match against your job skills and attributes.
The personal summary statement should be 30 to 40 words long. It should cover what you have done, the experience you have gained, the skills that you have learnt and the personal attributes you will bring to the job.
Although not directly part of the job summary statement you should have prepared a number of job related examples to substantiate your claims. Having said who you are and what you have done you can, if allowed the opportunity go on to explain through this series of job related examples. This should make clear the benefits you bring to the organisation.
The final point about listing the job related benefits is key to your success. The job interviewer wants to be able to picture in their mind exactly how your job candidacy can benefit their organisation. A list of job related skills and attributes is one thing but listing the benefits you bring to the job is much more powerful.