Hmm, both google links from safari and links in mail are still working for me.
My recipe is just a guess since I have exactly one case to work with, and I did a lot of stuff so I don't know what was important.
I don't know about you all, but I have hundreds of apps. I'm curious if that is true for others.
Obviously the problem we are having is not happening to 99.99+% of other people using 9.2.1, or we'd see a lot of forums with this thread active.
I know that my configuration goes back to pre-7.0 days, so I think it may have accumulated a lot of strange stuff that has been carried along during the OS upgrades.
Doing a fresh reinstall from a backup is likely to restore all that old cruft.
Maybe people could go into Settings > Privacy > Diagnostic & Usage data and tell me what they are seeing in there.
I'd bet there are a lot of crash logs. Maybe send a screen shot? There could be a lot of clues about which apps are causing problems in there.
I saw a lot of JetsamEvent-xxx logs that I think are caused when it runs out of memory and has to kill off some processes.
Anyway, here are more things that I did, and maybe someone can see if they can get another example of a "cure" and a better recipe.
Settings > Reset > Reset All Settings
Also, if iTunes wants to upgrade to 9.2.1 even though you are running 9.2.1, then go ahead and do the install.
Get rid of partly deleted apps:
Go into Settings and scroll down to where all the apps are.
If there are apps at the top of the list with a generic/blank icon (sort of an X) then those need to be deleted.
You can try to delete them from Settings > General > Storage > Manage Storage, but that often doesn't work even though they disappear, the are still there the next time.
The only way I've found to get rid of them is to find the app that we deleted and reinstall it, and then delete it. This is not always easy, but the version number and size of the app is still there and sometimes you can find it using a google search like site:apple.com "version 20.1".