I am adding house numbers in Geneva right now, and i did some tests for searching streets with the openstreetmap web site. In general i have no problems, but i found that i can’t find addresses with a long street which goes through several towns. The street name is ‘Route de Saint-Julien’ (French name). If you look for a given number, for instance ‘183 route de Saint-Julien’, with this street, it will display all streets with different towns in the search results. But if you click on one of these town, the map displayed has nothing to do with the street number. If the map is near the address when you start the search, the search result is working fine.