Why is there so much spam on Twitter?

[SaskGuy]

I logged into my Twitter account, only to find hundreds of Twitter blogs in my "following" list that I never followed. While I was logged on, someone else was added to my list.
Also, when I go to the homepage, I don't see posts from any of the people I follow. Instead, I see posts from people I'm not even following! One of them is some damn fashion designer I never even heard of.

How do you use Twitter anyway? Are you supposed to be constantly battling spam, and when you want to see posts from people you're following, do you have to click on each individual person's homepage?!

[David C]

If they are following you, you do not have to follow them back. you can block them from following you. Twitter recently made changes to the way the timeline works. Blocking unwanted users should remove their posts from your timeline

[Trickyt]

If you are seeing posts from people you never followed it sounds like you are using someone else's account. This could happen if your phone is second hand. Otherwise, someone has hacked your account and is using it. Change your password, then delete all the people you are following.