About a couple of weeks ago, Google increased the size of the title tags to 70 characters instead of the original 65 characters. This will allow you to add an extra word to your title tags and will help your site to target an extra keyword.
Title tags is on of the important factors in ranking your site. Google uses over 200 factors to rank your site.
I have tried increasing my title tags to 70 characters and it works. I heard some people saying that it even goes beyond 70 characters and that it even rotates to the second line but I have not confirmed that yet.