Hi Douglas -
Good pickup - the whitepaper aims to map vendors' functionalities in a buzzword-free fashion: "OneBox" is a little obscure, and "ExtraResults" and "ExtraSearch" aren't much better. Generally, when describing these functionalities, "Concurrent Search" is the phrasing that seems to best explain it.
The 'external search services' support isn't natively provided by Funnelback, but given that the sole inputs are a search endpoint, a query and an XSLT template for transforming XML, I'd look to solve that use case via:
- client side with asynchronous requests to the external provider, templating provided by your Javascript templating library of choice, or:
- server side using Funnelback's built-in Freemarker template engine to template up the XML
See also:
http://freemarker.org/docs/xgui_preface.html
https://docs.funnelback.com/freemarker.html