I think current model is OK. Companies using OSM data know that osm.org is not competition for them. They can give back to osm.org without fear to be smashed down in future with non profit giant-like-wikipedia-foundation living from donations.

Though it should be more clear that osm.org is just presentation of what is possible and recommending other maps and apps. Just something like a link to list of alternative styles/maps and offline apps on osm wiki.

České fórum:
http://forum.openstreetmap.org/viewforum.php?id=47

Český mailing list:
http://lists.openstreetmap.org/listinfo/talk-cz

Najprv si však skús prebehnúť články:
http://wiki.openstreetmap.org/wiki/CS:Main_Page

Na editovanie môžeš použiť prehliadač, stačí hore kliknúť na kartu Edit. Osobne však preferujem samostatný program na editovanie mapy - JOSM:
http://wiki.openstreetmap.org/wiki/JOSM
(stačí mať nainštalovanú javu, spustiť, stiahnuť dáta k zvolenej oblasti)

(ak sa ti náhodou niečo podarí zmeniť omylom, vždy sa môžeš vrátiť o krok späť alebo jednoducho pri skončení neukladať zmeny na server)

Here is comparison OSM (from JOSM) and slovak cadastre
http://img440.imageshack.us/img440/2455/josmokapor.png
housenumber 3 stay on landlot 2316/40 and there are two another land lots which belong to this house 2316/72 (:/72) as front yard and 2316/73 (:/73) as backyard. Of course, street is another land lot and field behind backyard on west (right) is another land lot.

Why not create buildings like here:
http://www.openstreetmap.org/?lat=48.878309&lon=18.044482&zoom=18&layers=M
e.g. housenumber 1 is different bulding from housenumber 3 and land lot border between them, that thin line in Mapnik image is land lot border.
this is how it look in real (its from real estate web, green house and another brick house):
http://www.vety.sk/fotky/0015/1578_12541.jpg?r=9827

IMHO, cadastral border can be useful for buildings, but you can create two buildings with few nodes which share both of them and use existing building=yes for these 2 closed areas.

BTW, cadastral border (land lot border) in Slovakia is defined as border of administrative boundary, border of cadastral office, border of built up area, property boundary (?ownership boundary?), boundary of tenancy, boundary nature of land usage. IMHO a lot of not so useless data.

(as you can see, english is not my native language)