> agent.maxSockets: By default set to 5. Determines how many concurrent sockets the agent can have open per host.
This stops you accidentally overloading a single host that you are scraping. It would not (assuming it works as described) affect your app if you are making requests to many hosts to collate data. Many applications (scrapers like httrack for instance) implement similar limits by default. If you are piling requests onto a single host but you either know the host is happy for you to do that (i.e. it is your own service or you have a relevant agreement) or have put measures in place yourself to not overload the target then by all means increase the connection limit.
You're close, but the rub is, every single http request uses the same agent (globalAgent), unless specifically passed an individual http agent or "{agent: false}" in configuration. So it is effectively a global connection pool. This has caused all kinds of performance issues in production applications. It can be easily shut off but it is easy to miss in the docs. The default of 5 has met its demise in 0.11 - the new default is Infinity.