If you put an advertising block (*) on your listing, telemarketing firms are no longer permitted to contact you.
local.ch does not sell addresses for marketing purposes. However, local.ch does not take any responsibility should these advertising blocks be ignored by third parties, e.g. if addresses are illegally copied from local.ch directories. When you enter a competition, for example, there is a chance that your address will be collected and used for marketing purposes by the company running the competition.
If you wish, you can also have yourself added to the "Robinson List for Addressed Advertising Material" and the "Robinson List for Direct Sales" (door-to-door sales): http://sdv-konsumenteninfo.ch/
More information is available at http://info.local.ch/your-listing/private-listing/advertising-block