Good question Rohit. A lot of people ask us this question about specializing in an area of digital marketing such as Search Engine Marketing, Search Engine Optimization (SEO) or Social Media Marketing. I don't advice people to start with specialization at this stage for following reasons:
Synergy between different channels: In order to improve performance of SEO campaigns, Social Media Marketing plays a role. Similarly, in order to maximize the value of leads generated through Search Engine Marketing, Email Marketing, Inbound Marketing & Web Analytics are important areas to know.
Senior marketing roles to people who know entire digital marketing spectrum: Professionals who know the entire world of digital marketing would be able to take up senior roles and play bigger role in organizational growth.
For the above reasons, it's important that anyone who's serious about career in digital marketing should focus on knowing digital marketing holistically. There are few scenarios in which specialization is important:
Leading a large team in a digital marketing agency: In large digital marketing agencies, there are specialists teams. For e.g., a large Social Media Marketing practice team, which requires someone to lead.
Specialist required for large/complex campaigns: In some large corporations (e.g. large e-commerce businesses), specialists for SEO, SEM, Social Media Marketing are required.
Given what I've mentioned above, I would advice to acquire skills in both Social Media Marketing and Search Engine Marketing even if you plan to specialize in one of the areas in future.