http://www.shodhel.com/
Although there are many apps that let you keep list of things (workflowy, thingist, notational velocity for MAC) it lets you access lists right from search box.
With special syntax (<list name>.<item to add>) you can add items to existing list. Or access existing lists with <list name>. This <list name><dot><item> syntax is optional after first use.
Using it as default search engine is privacy safe and doesn't increase search latency.
Hope you like it. Please leave your feedback.
@Workflowy, Notational Velocity users: Why you won't use this?
@Vimperator Users: Would you like to access something like vimperator from search box? It won't need plugin install.
