In all, these sites will contribute about 70,000 listings from the start to the Fairmarket network.

In 2008-09 the site contributed £4.4m to Viridor's profits.

"The site contributes to discussion of pan-ethnic solidarity in a positive way," he said.

Historical sites, such as those in the centre of Norwich, also contribute to tourism.

Many previously unknown archaeological sites have been identified through the scheme and it has contributed greatly to the level of knowledge of the past.

The site has contributed significantly to the geological record (for calcrete soils).

Rogue sites and their operators contribute nothing to the US economy.

The site contributes to the bank of knowledge regarding North American history and hunter-gatherer communities.

They say the site on the Persian Gulf complies with international treaties and does not contribute to nuclear proliferation.

Both sites also contribute to their parent sites' holiday gift guides.