A new study has found less than two thirds of iPhone apps are used more than 90 days after they are downloaded.

Conducted by Flurry, the study shows that 67% of apps are used more than 30 days after they are downloaded, 32% more than 60 days after and 25% more than 90 days after.

News-based apps scored highest on retention over a 90-day-period at 43%, as well as frequency of use at 11 times per week. Entertainment ‘gimmick’ apps, such as iPhone Lighter and IQ test, had a retention rate of only 12% over the same period and tended to be used very few times per week.

Social networking apps were found to have only a slightly better retention rate than ‘gimmick’ apps, at 14%, and were used six times per week.

BrandRepublic reported, despite the over two billion iPhone app downloads, that the research raises questions around mobile apps value as a brand building tool.

The study was conducted across Apple (iPhone and iPod Touch), Google Android, Blackberry and JavaME platforms.