书信：传统、有心意、表达感情复古细腻~
时间慢、周期长~
despite a traditional way of commmunication,letters is more caring,and much easier to express the feelings.but it takes longer time to get response.
Email：即时、方便、快捷,表现形式多样~
书写体,缺少亲切感~
Emails are fast and convenient.though you can put many colorful things into them,they are not as vivid as you write a letter.