eBay 'most popular brand' online
It scored the highest in terms of how positively it is perceived on the net, compared to McDonald's which had the most negative perception online.
Microsoft was the most prominent company name in the index, but it was the sixth most negatively perceived.
The DEX index was calculated using a scoring system which works out popularity across the net.
"The internet is fast approaching television in terms of influence on consumer behaviour and therefore big brands cannot afford to neglect the issue of how their brand is perceived on the web," said Ben Coppin, chief of Envisional.
"For a brand holder, gaining any kind of useful information about a brand or company's standing on the internet - particularly in comparison with competitors - is tremendously difficult."
eBay has recently had an advertising campaign on UK TV, and has seen its profits boosted too.
The success of the PayPal online payment service has helped to take sales over the $1bn mark, eBay said. It is relying on emerging markets, like China, to add more users to its auction service.
McDonald's has featured in the news over the last year as the result of the Supersize Me film, as well as the conclusion of the McLibel case, the longest running legal case in English history.
The fast food giant has responded to criticisms a result by introducing healthier menu options, including salads.
It also put adverts in five newspapers saying its food should be eaten as "part of a balanced diet".
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