This whole indexing business worries me. They actually store my data internally to provide these "instant search" capabilities. Im pretty sure this goes against terms of API use of many data providers. Linked in for instance says the following at http://developer.linkedin.com/docs/DOC-1013

"3.4 Data Storage and Conversion. You may not store or cache any Content returned or received through the APIs, including data about users, longer than the current usage session of the user for which it was obtained, except for the alphanumeric user IDs we provide you for identifying users, unless and to the extent that such storage or caching is expressly allowed in the Platform Guidelines. You may store the alphanumeric user IDs we provide you indefinitely unless we terminate your use of the APIs for breach of these Terms. The restrictions of this Section do not apply to “Independent Data,” which means data that users provide directly to you, provided that you cannot convert data received from the APIs to Independent Data (e.g., by obtaining it from the APIs and asking the user for permission); Independent Data must have been separately entered, uploaded, or presented to you by the user of your Application."

Basically Linked disallows storing data directly or converting/hashing/indexing it and then storing it. It only allows storage of user ids.

Yet greplin is getting away. I suppose they pay for special data licensing.