Another reason fueling the boom in fast-growing technology services is , which, when done right, can virally spread awareness of a firm with nary a dime of conventional ad spending a. legacy systems

App stores

Explanation:

For the boom in the fast growing technology services, the app stores played an important role for creating an awareness among the audience at a large. Also at the same time it creates a positive impact for an economy, also the transaction cost also falls, there is a less barriers to entry and the rise in the customer trust, loyalty and security

Hence, the correct answer is app stores

the first successful, urban blues recording, selling more than 75,000 copies, was made in year 1920.

mamie smith recorded the first commercially successful example of the urban blues,   with the recording of “crazy blues”."crazy blues" was recorded on august 10, 1920, in new york city. within a month of the release of “crazy blues” it had sold 75,000 copies.