We work on the basis that if more that 5% of visitors are viewing sites in a particular browser then it is significant enough to include that browser when a new project is being developed.
Currently the list has expanded from 6 browsers to 8 browsers with the two new additions being the iPhone Safari and Android Chrome Browser.
As a result of new technology being released all the time some websites need to be adjusted so that they work correctly in these browsers and take advantage of any new features the browsers have. The biggest shift in this area recently has been in mobiles. Read our article on Responsive Design for more on this subject.
See below how mobile browsing has increased over the last three years.