Many Facebook users already put hashtags in their posts. Google Plus users do it as well, and Google Plus has adapted to the trend. Facebook should follow suit; it's clear that Facebook users want to use them, and having them supported would be an added plus of continuing to use Facebook.
Facebook is facebook. Twitter is twitter. It's that simple. That is all i have to say about this. If hashtags your supported by facebook, the two companies should work together no? Just saying, I guess it would be a bad thing if # your supported through facebook, but again, # are something that makes twitter unique, why take away the uniqueness of it?
Facebook should stay away from hastags. That is what Twitter is known for and I do not think that it would be smart for Facebook to get the follower label. Facebook should stick to what they do and not try to take ideas from others. What they're doing is great and has been proven to be successful.
The point of Facebook is to have a sort of blog with a close circle of people whom you may know where you share your status, photos, videos, etc. You can have a public Facebook or a private one or you can make a page. Hashtags are used to trend words or phrases and it is very public. Using hashtags would completely eliminate the privacy of that particular status, and who knows who could have seen that status. For example if someone posts a status saying, "Party at my house, (address here) #homealone" That status right there could have dangerous consequences and it is not safe at all. Most people turn their Facebook private so that only themselves and a certain group of people are able to see their posts. Hashtags would eliminate any privacy Facebook may have.
The hashtag is Twitter's trademark, to see what's trending. Facebook doesn't need to use them. They should remain as individual and separate as possible. Just like Twitter doesn't have "likes", Facebook shouldn't use hashtags. The people that use hashtags on Facebook tend to write pretty pointless words anyway, not really relevant to their previous status/comment.