Evernote is a cross-platform note taking and idea capture utility that automatically syncs to the company's cloud service. It allows you to easily save websites, photos, and text for later usage or collaboration purposes.
For alternatives, see here.
Con Security issues
Evernote had their entire database hacked and compromised including customer user passwords. They responded by locking valid users out of accounts and forcing password changes but are still vague about their own security policies. They do not have a good track record for data security. They also do not offer local personal encryption of entire Notebooks as Microsoft OneNote does.
Con Pay for offline use, search, and other functions
The free version of Evernote is highly limited. You have to pay if you want to access your notes without internet connection, search your notes or documents, or upload large amounts of data. The free version allows you to upload 60 MB of data per month, which is about 20 to 30 iPhone camera pictures.
At a certain point, they started charging you for "advanced" capability, which includes searching your own attachments.