Dotstorming is a good tool for gathering ideas from a group and then having the group members vote on those ideas. I have introduced Dotstorming to hundreds of teachers in workshops over the last two years. As recently as earlier this week I had teachers commenting on how much they liked using Dotstorming with their students. Yesterday, Dotstorming changed to a freemium service. Now you can only have five boards (collections of ideas) in a free account before you either need to delete a board or upgrade to a paid plan at a cost of $5/month.
In the same email announcing the fee-based plan, Dotstorming highlighted the relatively new options to download the contents of your boards as spreadsheets and the option to display names on your boards.
If you're interested in seeing how Dotstorming works, watch my video embedded below.
There are other services that can be used in a manner similar to Dotstorming. Padlet is one that comes to mind immediately. I have a set of Padlet tutorials embedded below.