On Blockchain.info, how many addresses can I pass into one API call? Most of the Blockchain.info API calls (eg Unspent outputs) allow you to specify multiple addresses in one call separated by "|". Is there a limit to how many addresses I can pass in? 

If I pass in 1000 addresses, does it still count as one API call toward my rate limits?
rate limit counts each request you send to the server, so doesn't matter what parameters are you passing.

I'm talking about Nginx and apache rate limits techniques which are used by blockchain.info.

Blockchain has no limits for requests but the limit is coming from Nginx and Apache (default config), unlike blockcypher which counts each address as a request.