Not to be outdone by Facebook — the social network just launched a mobile share button — Twitter has added the ability to share tweets by email directly from its website.

“You can email a Tweet to anyone, whether they use Twitter or not, right from your Twitter stream or from the details view of any Tweet,” explained Twitter. While retweets are convenient for sharing content with other Twitter members, the new share option targets non-members.

Rolling out to everyone over the coming weeks, tweets can be shared by clicking the “More” icon next to the reply, retweet, and favorite buttons. Individuals will be able to add their own comments, and the email will be signed with their Twitter account.

While certainly not a new functionality — the feature has been present in Twitter’s mobile apps for some time — it does work in favor of the company and its advertisers. There’s no doubt that Twitter will use the email addresses members share to market its services to non-members.

And as TechCrunch pointed out, the social network wants these people to sign up, but it doesn’t necessarily need them to tweet. It’s happy to have “passive content consumers” as long as Twitter can serve them targeted ads. The downside here for brands is that passive consumers don’t add to your engagement metrics; however, it’s possible that some newcomers will convert to followers.

[Via: AllTwitter, Image credit: Andreas Eldh]