One popular use case for data grids is to cache and cluster HTTP sessions in servlet containers. This provides servlet containers and Java EE application servers with the following features:
Fast access to HTTP sessions, as they're cached in memory
Distribution of HTTP sessions across a cluster. Allows for failover and high availability between servlet container or app server nodes.
JBoss AS and WildFly already use Infinispan for HTTP session caching and clustering.
Jetty can be set up to use Infinispan for HTTP session management, using this adapter.
Creating plugins for other servlet containers and app servers should be easy enough, following the pattern used by JBossAS/WildFly/Jetty above. Please see the open tasks below, contributions accepted!