Edmodo
Edmodo is an online interface where teachers
can work in groups to organise classroom and extracurricular activities. The
system can be used to work with entire classes or smaller groups created for
lab and other projects.
Teacher registration requires only an email address. After you register, you can log in to the system and start using it right away. You should start by configuring your profile. Here you can set the URL of your home page, pick an image from the system or even upload one of your own.
Teachers can create various work groups. Whenever you create a group, you get a system-generated code. You can only connect to the specific group if you use this code. You only need to provide this code to those students you would like to invite to a joint project.
You can post messages to students on the group's message board right after you've created a group. You can publish notes with files or links attached. A simple poll is an effective tool to maintain student interest or whenever various options and opinions may create a debate. Creating a poll is very simple. You only have to click the icon, type the question and the possible answers and then click Send to post the question to the group. If you have multiple groups, you can specify which group the specific poll is for.

Students can log in to the group created by their teacher without registration. All they have to do is click on the "I'm a Student" button on the Edmodo home page and enter the 6-digit code given to them by the teacher. After they log in, they can modify their profile, enter their email address, upload their own image and configure a number of settings. The most interesting of these settings is that they can identify their student type (e.g. visual, verbal) and pick a specific field as an objective for their studies. After they log in, students also get a code they can use to invite their parents to the group.

The group has a calendar and a document library. This latter can be connected to the teacher's Google Drive, but individual files can also be uploaded.
The teacher can give assignments to the group members with a description and a deadline attached and, optionally, with a link or file from the library. Each assignment or activity is displayed on the group's message board, enabling students to comment or ask questions directly. Teachers can award students' work with various badges. These badges can be attached from a set to the student data sheet but custom badges may also be used.

There are a number of communities on Edmodo to which teachers can connect and get useful information on methodology or technology.