Stand Up Or Sit Down
Then, we at Fark agreed to jump in, as did Wikipedia, Google, BoingBoing. We jumped in because it made sense to do so, because SOPA/PIPA would catastrophically affect us. Of course, we took it our own unique way and Fark sarcastically "Whited Out" instead of blacked out. It's cause we're just that way (of course, it helps that I'm the asshole in charge of things like that).
Then the rest of the whole internet joined the chorus, because it made sense to do so. Joining the chorus is easy, because your voice can blend in and still sound harmonious.
Solos put all the focus on you.
Taking a stand is only taking a stand when you have to brace yourself to be knocked over. Joining a group when the group is already there is just going with the trend -- and when something's right, that's a fine thing to do. But there's no getting around the fact that saying "Oh yeah, me too!" is taking a partial stand at best. When the crowd shifts and heads a different direction, you'll go that way too, because you're not out front seeing where you're heading.
If you take the metaphor literally: taking a partial stand leaves you bent over. More than that, it leaves you off balance and makes you easier to push over. Be the first one in the crowd to stand up and clap your hands when you see something worth clapping for. Don't wait to clap because everyone else is clapping.
Movements don't happen because a group of people willed it, they happen because a leader stood up and took a stand, and people followed.