Dear Vijay,

I assume you want to know the difference between the service cloud and sales cloud.

aving the right information in front of the right person at the right time is critical in providing customer support.  Customers expect to have most of their questions answered instantly and increasingly get frustrated if an answer is not available within minutes. Being able to provide this information to your customers in real time used to be a hallmark of superior customer service, but now is expected as standard customer service.

Salesforce.com has several options available to you to ensure that you’re keeping every customer satisfied.

Functions in the Sales Cloud

If you’re currently using or are implementing salesforce.com’s Sales Cloud, you have the foundation necessary to capture and resolve customer questions or issues.  The basic functionality includes:

Cases—you can track customer inquiries, escalate issues requiring specialized support and monitor your agent’s productivity.
Solutions—Equip your customer service team with the answers to your customer’s questions and even make the answers available to the customers on the web so that they can find the answers themselves whenever they need them.
Web-to-Case—if your customers can’t find what they’re looking for on the web, you can have them log a case directly from your website that immediately enters Salesforce.com for agent resolution.

Additional Functionality in the Service Cloud

If you have a more complex support requirements or more active customer service team, you should consider Service Cloud licenses.  Service Cloud licenses provides the standard Sales Cloud functionality for your users, and add additional functionality to better equip your team to provide service more efficiently.  You can have Sales Cloud and Service Cloud users in the same instance of Salesforce.com.  Additional features of Service Cloud include:

Agent Console & Customizable Layouts—This helps your agents access relevant information about the customer with fewer clicks.  You can design the console to maximize this efficiency.
Entitlement Management—if you have Service Level Agreements that provide different levels of support for your customers, you can use entitlement management to ensure that you deliver the proper service level including first response and resolution times. You can also incorporate automated processes that provide instructions for reps on the best way to resolve cases.
Access to Live Agent Web Chat (additional fee above Service Cloud license)—Incorporate live chat from the web to ensure that your clients get answers from you in real time without a phone call

Please follow the below link for more information

http://www.akacrm.com/blog/35-sfdc-insight/198-service-cloud-vs-sales-cloud.html

Best Regards
Naga kiran