Google has blacked out their logo to protest SOPA and PIPA. But Microsoft Bing and Yahoo have done nothing to protest loudly on their home pages.
Google's logo takes you to this landing page with some details on the regulations and a way to take action and fight against it. Like I said, Yahoo and Bing are pretending nothing is happening.
Here is the Google Logo:

The only other search engine doing anything, as far as I know, is DuckDuckGo:

Ask.com has an ad:

Wikipedia was the most vocal about this protest:

Reddit also:

I should note, Yahoo owns Flickr and Flickr does allow people to darken their own images as a protest, but Flickr is not doing it automatically, which I guess they should not do.

Even Search Engine Land went a bit dark, not completely, to protest SOPA:

And we have our own theme, kind of like Search Engine Land:

So Bing and Yahoo, what is up with you?
Forum discussion at Google Webmaster Help, Google Web Search Help, Google Blogoscoped Forums, and DigitalPoint Forums.

Comments:
Shamer
01/18/2012 02:27 pm
Shame on Yahoo and Bing!
EastCoastMustangClub
01/18/2012 03:35 pm
shame on yahoo and bing and other major sites, I run a small #nj #forum and I'm in on it!
STOP GOOGLE
01/18/2012 05:19 pm
Google is "saving" the internet to rape and tax it. We need to STOP GOOGLE, especially now that they sell rank
Snoozamannen
01/19/2012 06:14 am
You are polluting the Internet by posting stupid comments. SOPA is seriously bad sh!t.
Janes Hoyyt
01/19/2012 12:43 pm
Your an idiot
liberalrepublic
01/22/2012 01:51 am
google is good at PR. it did not blackout entirely. search was wrkin and the ads were displayed. all i saw was little bit of black smudge