Direct messages on Twitter?

[From.The.Hollow]

So I've had my twitter since April, and have gotten 3 direct messages. I got my third one today, and before that, I thought you could only send DM's to people who you follow & who follow you. Except the DM I got today was from somebody I follow, but who doesn't follow me. Does that make sense? I was just curious as to how that worked, because like I said earlier, I thought the only way to DM somebody was if you two followed each other. I also have checked my profile and don't have a "message @_____" on my page. Just curious as to how it happened. It's not a big deal (can't stop smiling since this last message was from a favorite artist of mine haha) but I was just curious as how he could DM me.

Sorry if this was too confusing. If it is, just let me know & I'll fix it =]
@Rafael: sorry... can't do what anymore? I'm confused haha

[Rafael Snitchers]

Thats because of a old update,now you can't do that anymore.

[SL]

You can send DMs to everyone who follows you, you do not need to follow them.