Commercial use in an application - licenceable? (ODbL)

This is the wrong place to start a legal discussion.

For discussions please usr the legal-talk mailing list, if you have specific question to the licensor (the OSMF) please see http://osmfoundation.org/wiki/License or contact the LWG at legal-questions@osmfoundation.org

If you display anything on top of an OSM map then the two data sets are completely separate and nothing happens, license-wise.

If you use OSM data to derive the location of a point (either by letting your user click on the OSM map to place the point, or by using OSM street names, house numbers, and boundary information to match an address to a coordinate pair) then you're in murky waters. Some people will say it's trivial, others will say you are deriving information from OSM. There's also a distinction to be made between doing this just once or on the fly, or doing this often and saving the results in a new database. The jury is still out on this one and you can see different possible interpretations in the work-in-progress geocoding guideline.

If you are placing pins on an OSM map (from your own tile server) and those pins are being placed based on a latitude and longitude you already know (generated from your own app), that surely remains a Collective Database and thus does not require releasing your customer information. (Surely lat/long is far more trivial than name/locality.)

Correct.

If you are placing pins on an OSM map and those pins are being placed based on street address you already know (from customers giving it to you), isn't that too a trivial match and thus a Collective Database and does not require releasing your customer information?

Correct.