Why? Because the FLOCK team joined Zynga! This means that if you find that you really really really like Zynga, be forewarned that someday the "team" will bounce and pull your little rug right out from under you, the same as they did for many happy FLOCK users!
Here's a snippet from the website:
Official End of Support FAQ
Why is Flock shutting down?
The Flock team joined Zynga in January, 2011 and is now working to assist Zynga in achieving their goal of building the most fun, social games available to anyone, anytime -- on any platform.
Is there any version of Flock I can keep using?
Flock will no longer be actively maintained, which means you can keep using the product, but key features will stop working after 4/26/11 and over time the browser will no longer be secure as software updates and upgrades will no longer be provided.
In other words, flocksters, the "team" says F*** YOU!
(Lucky for me I have an older version of Flock that doesn't require signing in to work. I'll be uploading that when the current flock dies for good.)
via USA Today ::: Flock is a casualty of the social nature of the Web and Facebook's Open Graph initiative. Web denizens now carry their social graph with them via Facebook and not through the browser. Its shutdown also calls to mind the rise and fall of the once great Flip video camera, which is also being discontinued