Is it safe that unknown people follow in twitter?

[Jason]

It depends on what you use Twitter phone. Ideally it's not normally a good idea to have people you don't know follow you, especially if you post personal stuff. Things like your location, the restaurant you ate a yesterday, pictures of your girlfriend and things that point to you are generally a bad idea to share with the whole world. Since your privacy settings are off in Twitter it doesn't matter who follows you anyway because anyone can look at your tweets.

If you're just retweeting other people's stuff and links to news articles or other miscellaneous things like that then it isn't really a big deal. But I would suggest you enable your privacy settings and block anyone who is following you that you don't specifically know.