Investis has altered its corporate website ranking as of the last quarter of 2010 in order to give more weighting to how effectively companies are using social media.

Their corporate website ranking of four national indices - the FTSE250, the MDAX, the SM120 and the ATX20 - now looks at the web presence of individual companies on social media channels, such as Twitter and Fa  external to their corporate sites.

The Swiss SM120 leads the field in social media according to Investis, and the Switzerland-based company Nestle was the highest scoring company, due to their concerted efforts to establish a corporate presence across social media platforms and the recent launch of a corporate iPad and iPhone app.

The FTSE250, where 10% of companies failed to score at all in the social media category, did not fare so well in the rankings. The average score across 12 categories, including CSR, Multimedia and Careers, increased by only 0.17%, with scores declining in 8 of the categories.

Investis has made changes to its ranking system in order to maintain relevance in the new landscape of web usage and social media - but this has coincided with the slowest rate of improvement since it began benchmarking companies in autumn 2008 and falling off in all the indices surveyed.