Last week Pinterest opened its online service to the general public, ending a multi-year period in which users who signed up had to wait to be admitted by the company.

MSN: Pinterest unveils Android, iPad apps

Google is playing it canny by only releasing the product via invite to a limited set of users before being gradually opened up to the general public.

BBC: Google+: The new Facebook rival?

Privacy settings let users make these lists private, or available to their friends or the general public.

FORBES: Move up http://i.forbesimg.com t Move down

Descriptions of each item and videos, with expert curators speaking about selected items, provide context for users, and are intended to spark curiosity and encourage both students and the general public to learn more about the cultural heritage of all countries.

UNESCO: Communication and Information