The company has begun a project to analyse the online legacy information targeted at donors from the top UK charities by legacy income, in order to find out how to produce improvements.
Initial research has shown that legacy information is difficult to find and presentation of the information is dull.
The agency has also found that legacy information does not rank highly in the results from internet search engines.
"If it's not on the first page of the listings, people make the assumption that what they are looking for isn't there," said Matt Parkes, head of stewardship and legacies at Bluefrog. "This information should be easy to find, and it isn't."
The research is expected to be completed by the end of November.