How many Lithium data export options i can choose

Hi lfl1001,

There are three different APIs you can use to pull data from the community:

1. Community API v1 - Our original API which has a huge number of calls for almost every aspect of the community.
2. Community API v2 - Our newer API which features the ability to search using LIQL (Lithium Query Language).
3. Bulk API - Allows you to obtain a log of the various events and actions that have occurred in the community.

You might also be interested in reviewing details about implementing a federated search strategy. Although it's not the exact same use case, there will be a lot of similarities in how you obtain the data, and crawling is another option for doing so:

http://community.lithium.com/t5/Developers-Knowledge-Base/Implementing-a-federated-search-strategy/ta-p/7269 

I hope this helps!