If you see a bunch of purple profile pics, Timeline photos, and Twitter avatars today – don’t worry, everyone hasn’t uploaded a new photo from their iPhone 5 cameras. All that purple is for #SpiritDay, an anti-bullying awareness campaign first launched back in 2010.

For the third time, October 19th serves as Spirit Day – a day where people add a splash of purple to their lives (both online and offline) in support of LGBT rights. The national awareness day was started by a high schooler named Brittany McMillan.

“Ultimately, I want Spirit Day to make just one person feel a little bit better about his or herself, to feel safe enough in their own skin to be proud of who they are,” she says.

I’ll let GLAAD sum it up:

“Millions of Americans wear purple on Spirit Day as a sign of support for lesbian, gay, bisexual and transgender (LGBT) youth and to speak out against bullying. Spirit Day was started in 2010 as a response to the young people who had taken their own lives. Observed annually, individuals, schools, organizations, corporations, media professionals and celebrities wear purple, which symbolizes spirit on the rainbow flag. Getting involved is easy — participants are asked to simply ‘go purple’ on October 19th as we work to create a world in which LGBT teens are celebrated and accepted for who they are.”

So today, supporters will take to social media to show their support in a number of ways. Avatar-altering Twitter cause supporters Twibbon have a hub where people can tint their profile pics purple, as well as tweet and Facebook standard support messages. There’s also an official #SpiritDay Timeline cover photo available for use.

You’ll probably see social media properties getting in on the purple as well. Facebook will tint a few of their official pages purple, including their Diversity and Safety pages. Facebook has been a big supporter of Spirit Day from the start, even winning a GLAAD media award for their attention to LGBT causes. Yesterday, Facebook ramped up their anti-bullying initiative with a new safety page, videos, and a rededication to a national ad campaign involving its “Stop Bullying: Speak Up” project.

Facebook’s not the only one. Tumblr will also participate in Spirit Day, as will StumbleUpon, Hulu, and Instagram. More info on all the participants is available on the GLAAD website.

Of course, it’s not just about going purple in support. If you want to make a financial contribution, you can text PURPLE to 80888. That will donate $5 to GLAAD, GLSEN, and The Trevor Project.