Posts on Twitter -- tweets -- are about to undergo their most significant change in a decade. Most of the changes, like no longer counting photos and Twitter handles against your character count, are obviously awesome. However, one change has left the Twitter faithful a little confused: @mentions.

Pronounced "at mentions," @mentions is when you start a tweet with a Twitter handle, say "@WilliamShatner." Because Twitter assumes that tweets starting with a handle are replies to the owner of that handle, they're hidden by default in your followers' streams -- unless the follower follows both of you. Smart Twitter users have skirted this rule by starting such tweets with a period.

".@WilliamShatner is starring in another Priceline commercial." (I usually got around this by adding a superlative before the Twitter handle: "The awesome @WilliamShatner is ...")

The new rules let you start a new tweet with a Twitter handle without the need to add a period. As long as the Tweet is new (launched from the Tweet button on any platform) and -- importantly -- notlaunched from the Reply button, this will work.

Replies will still be seen by those following the included (mentioned) parties. This is the same as it ever was.

The new rules let you start a new tweet with a Twitter handle without the need to add a period.

If you do reply to someone, but still want every single follower to see the reply, you'll also be able to retweet your own reply to all of your followers. This is another part of Twitter's other upcoming big changes: the ability to retweet your own tweets. Right now, that RT button is grayed out on your own tweets.

This change shouldn't change the percentage of tweets to people you do not follow in your timelines. If someone you follow tweets about someone you don't by putting their handle at the start of the tweet, you will see that, because you follow the Tweet originator. However, if someone simply replies to someone you don't follow, that reply will not show up in your feed.

For now, though, nothing is changing with Twitter. The tweet overhaul will have wide-reaching implications for Twitter users, partners and the company's back-end operations. As such, it'll take months to roll out.

To recap:

• Start your tweets with "@'s!
  

• Retweet your own replies!
  

• Retweet yourself!
  

• Never start a Tweet with a period again.
  

Have something to add to this story? Share it in the comments.