Reason for direct source new visitor traffic.
Recently we found that out new visitors traffic has increased - which is now about 80% of total traffic. As we looked at the traffic source, to our surprise about 70% of new visitors traffic are coming from Direct/none source. Considering SPAM traffic we looked at the bounce rate and avg session duration (for new visitors - direct traffic), the values are decent and matches with website average. In these duration we did not had any PR effort that can increase the direct traffic.
Can anyone shed some light on this observation. What can cause direct source traffic for new visitors?