Video: Salesforce Service Cloud vs ServiceNow

With the Service Cloud you can meet customers wherever they are—including social networks such as Facebook and Twitter. Your agents also benefit from employee social networks that help them work together like never before. And because you get all the features a social contact center needs, your customers experience amazing service on any channel.
ServiceNow offers a portfolio of robust cloud-based products that automate and manage IT service relationships across the enterprise. Our products have the advantage of being built on a single cloud platform that consists of one user interface, one code base and one data model, delivering easy, automated upgrades. ServiceNow provides an intuitive and approachable user experience complete with expert services to accelerate time-to-value. ServiceNow free open-source alternatives are: osTicket, OTRS, Mantis
Face to face in the news:

2016 - Salesforce Service Cloud added new field service product

Until now Salesforce left field service to third parties like ServiceMax. Calls have come into customer service and have been processed in Service Cloud. While there is a connection to the customer record to let sales see when the customer is having issues, there has been no direct way to connect this information to people out in the field; Salesforce wanted to close this gap. And yesterday they introduced a new field service product they have dubbed Field Service Lightning. Besides, Salesforce key competitors like Microsoft and Oracle have entered this market recently and Salesforce saw this was as a significant missing piece.

2011 - Salesforce acquired social Helpdesk service Assistly to win over ServiceNow

Salesforce seriously decided to become the leading provider of customer support solutions. Its own solution Salesforce Service Cloud is already almost flying to space, but its price is also too cosmic for small business. Therefore, in order to land SMBs, the company decided to buy (for $80 million) the one of the two most popular SaaS Helpdesk services - Assistly (the second - is Zendesk). Assistly fits perfectly into the Salesforce's new Social Enterprise concept. This service allows you to communicate with customers via Twitter, Facebook, client forum, live-chat as well as via traditional channels (email and phone). At the same time support people work in one simple interface. Also, Assistly is known for its original pricing: it's free for one helpdesk agent, and the additional agents can use the service on per-hour based model ($1/hour). So if no requests are coming to support - your company pays nothing for the helpdesk.