A poll or survey tool can be used for formative assessment and typically questions are not seeking "right and wrong" answers. A game or quiz tool can be used formatively and will detect "right and wrong" answers.
Google Docs: Spreadsheets can be turned into forms that can collect survey data.
GroupMe: Group texting
Plickers: One device and student cards, paper + clickers = Plickers! See this tutorial.
Response cards - Alternatively, you can have students hold up flip cards with A, B, C, D responses that only you the instructor can see (you need to use card-stock). Student's raise their hands holding the card response choose, and you can quickly see the answer distribution.
Flippity: Easily turn a Google™ Spreadsheet into a Set of Online Flashcards
Kahoot: Teacher account and login page to set up Kahoot/game assessment, getkahoot.com and student access, www.kahoot.it
Playfactile: Create an online Jeopardy game
Plickers
Quizlet: A tool for learning vocabulary: Why is vocabulary learning so important? To understand a text, one must understand the words that represent the ideas or concepts. Studies confirm the high correlation (0.6 to 0.8) between vocabulary knowledge and reading comprehension (Baumann & Kame'enui, 2004; Pearson et al., 2007).
Quizizz : Teacher account and login page to set up Quizizz/game assessment, quizizz.com, and student access www.guizizz.join (learn more about Quizizz at http://learninginhand.com/blog/quizizz)