Money packets are the best way to send bitcoins over email or Dropbox, no account necessary.
A money packet is a shareable file which contains bitcoins, like a digital envelope for money.
This website lets you create money packets and claim their funds.
Recipients don't need a bitcoin wallet to receive funds.
Both parties can access funds in a shared money packet until the funds are claimed.
Your funds are never entrusted to a third party, including this website.
Money packets are protected by a password which you create.
This service is free (tips voluntary), open source, and runs only in your browser.