Web: If email is your tool of choice, then Planleaf will create collaborative task lists, where you can also add teammates, issue deadlines and add notes to completed tasks -- all with a simple email message.
The app is appealing because it doesn't require anyone to sign up, it's formatted as a checklist, and it works anywhere using email. You could use Planleaf to create a new task list every day, and CC your team or anyone concerned. They have the ability to add new items, edit current ones or tick the completed jobs.
To create a task list, just add a dash before each item in the list. Anything in the email without a dash won't appear, while the subject line of the email is the task list's header. You can add deadlines by putting the day or date in brackets -- (Monday), for example -- and people can be tagged by adding an @ symbol before their name. However, you will need to rely on your email client's search capabilities for finding the tags. Planleaf sends a daily email digest to show you the items due for that day.
While Planleaf could be used by individuals, it's best as a short-term team collaboration tool. Send a daily task list, have people check off items or add more, and it's all done on email. No apps, no fuss.