好久没改日记了，要不加你微信？好奇你能留做什么评论. Maybe it's one of the messages that your friend leave? I don't think it's a joke or mockery, maybe it's a greeting or asking for opinions？ 好久没改日记了：He or She or you haven't updated the diary in a long time.(like greeting words, or just state a fact) 要不加你微信？：Can I add your Wechat?（maybe he wants to contact you for further conmunication, also make friend with you ） 好奇你能留做什么评论.：I’m curious that what will you write in comment. （waiting for your comments, maybe your words is interesting to him?）