Answer:
In simple words, the first mover advantage that the company get is that they set the standard for the product or service offered. Also, as there is a development of a brand new market, one can establish a strong customer base. The power of pricing also stands with the company.
In case of Yahoo, the company get the recognition among people very easily. Yahoo came out when people were starting to get interested in technology thus they were recognized as a symbol social media platform.