Social media is a blessing and a curse when it comes to pitching journalists. While Twitter, Facebook, LinkedIn, Foursquare and Instagram — yes, Foursquare and Instagram pitches happen — present many new opportunities to forge connections, it's very easy to step onto inappropriate turf.

Because the dos and don'ts of reaching out via social media can be messy, we compiled some solid rules for when it's cool and when it's creepy to contact a journalist. Here are 10 tips on how to pitch a journalist on social media, largely based on the experiences of Mashable's editorial team.

Let us know in the comments if you have other best practices for pitching, favorite ways to be reached or disagree with our list.

1. Twitter can be a great place to reach out.

Generally speaking, Twitter can be a great place to pitch journalists who are often very engaged with Twitter. As somewhat public figures, journalists treat their Twitter accounts at least partially professional, so they'll likely be happy to chat with you on Twitter about topics relating to their beats.

That said, many journalists receive a ton of pitches on Twitter, so be mindful of your first approach. If you just tweet "Hey reporter, I have something I think you'll like — DM me," you're leaving the journalist absolutely no reason to reply. Try to include a link to some news or @mention the brand or organization you're representing. If journalists recognize the company or are interested in the link you share, they're much more likely to reply.

An even better approach is to build a relationship through personal or funny interactions leading up to your pitch.

2. Don't ask a journalist you're not following to DM you.

If you're not a regular user, it can help to master the Twitter basics. You want to be careful with the Twitter lingo you employ, as well.

For example, if you tell a journalist to DM you her email address or just to follow up, make sure you're following her. You can't DM a user who doesn't follow you. Furthermore, don't ask a journalist to follow you so that you can send her a DM; it's impolite and unnecessary. Simply follow the journalist you're messaging and tell her to DM you her contact information.

3. Facebook is for friends, and friends don't pitch friends.

Journalists by and large never want to be pitched on Facebook. Even though Facebook now has many non-social uses — from media organizations sharing breaking news to the Follow feature — this doesn't mean the network has turned all business. Journalists, especially ones who consider their Twitter account to be an extension of their reporting, want to maintain some semblance of privacy on Facebook.

Facebook messaging also includes a technical hurdle. If you try to message someone you're not friends with, your message will land in their other messages folder, which likely goes unchecked.

Last year, Facebook rolled out the ability to pay to message people you're not friends with. But just because the feature exists, it doesn't mean you should use it, because Facebook is a social network for friends.

You should also avoid creative alternatives to messaging, such as commenting on cover photos or public shares with pitches.

4. Don't follow up more than once.

This point is short and sweet, the way your pitches should be. Follow up twice, shame on you. Follow up three, four, five or six times, you're spam.

5. Don't contact one journalist to get to his colleague.

Some journalists get way more pitches and Twitter messages than others. And, yes, a journalist on Twitter with fewer interactions and followers may be more likely to spot an @mention, but do not go through a junior journalist to get to his colleague.

A Mashable intern received the following message about one of our senior reporters: "I saw her number of followers and thought it would be easier to reach her this way."

Don't be that person.

6. Know the journalist's beat and the publication's content before you pitch.

Before you pitch, do your research. Social media can be enormously helpful for that. Are you pitching a person or product that this reporter would find relevant? Does the publication you're pitching produce stories about related topics? Although these may sound like basics, they're ignored more often than you may think.

Conveniently, social media can help you learn about the reporters you're pitching. Are you pitching them a story related to the topics they cover or tweet about? I write about social good, which I've written in my author description on Mashable and in my Twitter bio. Yet, somehow, less than half of the pitches I receive take my focus into consideration.

Unless you have a close relationship with a journalist, you should not be asking him who is the best person to pitch at his outlet. It's your job to do the research and ours to determine your pitch's relevance to our audience and publication.

7. Don't ask for an email address that's listed on Twitter.

This sounds like a no-brainer, but make sure to check if a journalist publicly lists her email address before you ask for it on Twitter. Many journalists do list their contact information in their Twitter or Facebook bios. Be sure to check both before you send the "how can I contact you" tweet.

8. Personal email addresses and cellphone numbers are not for pitches.

We all have too much email, and we want our work emails sent to our work addresses so we can reserve our personal address for family, friends and non-work messages. Unless you're pitching a freelancer, be sure to send your message to a work address.

Cellphone numbers should be treated the same way, although unfortunately it's harder to judge whether a phone number with no extra information is a mobile or landline.

In the rare case a journalist publicly lists a cellphone number, you're free to pitch it. If you've somehow ended up with his cellphone number because he attended an event that required it for sign-in, you should respect his privacy and not call a number you know to be personal.

9. A tweet reminder about the Facebook message you sent saying you emailed a pitch is unnecessary.

It's appropriate to follow up on a pitch once, but that's two attempts total on all platforms — not two per platform. This means, if you tweet and email, those are your two shots. Don't send an email, tweet, follow-up email and follow-up tweet. That's overkill.

Furthermore, don't tweet a reminder about a LinkedIn message about an email.

10. Remember tweets are public; don't mass tweet pitches to several reporters and outlets.

If you have a story you really want to be picked up but have absolutely no idea what outlet or reporter may be interested, don't leave a trail on Twitter.

As soon as you pitch a journalist, they will likely click on your Twitter profile to learn more. If they see that your last 20 tweets are copy-pasted versions of the tweet you sent him, he'll quickly lose interest.

Additionally, don't pitch organizations by their Twitter accounts. Most news outlets receive way too many Twitter mentions for their social media team to read through, so your pitch will probably never be seen. Your time is better spent narrowing down which reporter would be the best fit for your pitch.

Images: Flickr, Repórter do Futuro, Richard Masoner, Roger H. Goun