LinkedIn is a business and employment-oriented social networking service that operates via websites and mobile apps. Professionals use LinkedIn to extend their network and catch industry news online. 
People also enjoy offline trade conferences, exhibitions, and local meetups. It helps them encounter new people and opportunities, gain more in-depth industry knowledge, and have unique onsite experiences. 

There are some limitations between LinkedIn online career service and these on-ground events for people to develop their network:
1. These events usually are temporary and short
2. Among hundreds of participants, it’s hard for people to reach out others who are not around them
3. It might be hard to find the old friends who are at the same conference
4. Sometimes the events last for two or more days, they may want an easy way to start a hangout with new friends.