Poll Everywhere Activity Types

Multiple Choice
MCPs are probably what you'll use most often. They're the workhorses most often used for quick formative assessment or for standard quizzes you intend to grade.
Deploy a simple MCP every 10 to 15 minutes to bring wandering minds back into the fold.

Word Clouds
Word clouds are a great way to gauge students' reactions to a topic, or to distill a topic to a one-word takeaway. They're also a ton of fun (you'll see words grow bigger and smaller onscreen as students send in their responses).
One of the favorite uses is a “before and after” activity. Ask students what they think of a topic before you cover it. Then do the same at the end of the discussion to see how students' perceptions of that topic changed. Note that students can enter multi-word phrases in word clouds by separating words with a tilde (~).

Use a Q&A to collect feedback during a lecture, or just leave one open at the beginning of class as an always-on comments/questions/concerns forum.
One popular use for Q&A: leave one open behind students as they give a presentation, encouraging the class to engage with the material being presented. Keep in mind that students can upvote their favorite responses, so the most popular float right to the top.

Clickable Images
Like word clouds, clickable images are a ton of fun and they're also quite flexible. Upload an image (or select one of the pre-defined images) and students click on it to respond.
Uses range from simple (ask students their Myers-Briggs personality type as an icebreaker) to creative (use a map to illustrate a journey).
Note that you can mark certain regions as correct, so clickable images can be graded.

Open-ended questions are exactly what you think: a simple, open-ended question. Responses can be displayed as a text wall, a word cloud, or a Spotlight visualization to highlight individual responses.
The most powerful part of the open-ended poll is its ability, through anonymous responses, to make difficult conversations more productive. Students tend to speak more freely when they know their responses are anonymous, which can lead to wildly productive discussions.
Note that your institution-wide account gives you access to the moderation feature, so you can automatically filter out profanity, or screen responses if you choose.

Rank Order
Rank orders are pretty simple: you input a list of items, then students drag them around to put them in a certain order.

Whereas all other activities are a single type of question, surveys are a string of activities tied together, in whatever order you choose. They're perfect as pre- or post-class assessments. To share with students, all you need is the survey link. Share it however you like: paste it in an email, keep it on the blackboard for students to write down, or share it on social media.

More reading on the different question types can be found here.