Q: Can I use twitter to interact with students during the lecture?

A: There is a real need to make sure that students remain engaged. Twitter could get students interested.
Guide to Using Twitter in Your Teaching Practice
http://blogs.kqed.org/education/how-to-use-twitter-in-your-teaching-practice/

"Twitter could be used as another method to reach students, to share content and provide information. The social nature of Twitter means you can ask questions, have conversations, and join discussions or debates.
Questioning and debating teaches us to think critically – a key skill no matter what you're studying – and online debate is a way to develop these skills. Hashtags create online communities where you can discuss a topic with your peers."
Source:  
Universities should use Twitter to engage with students

Q: I am looking for more interactive ways of teaching a big size class. It is challenging to engage students with clickers because they are limited to multiple choice. Could you recommend more modern engaging platform to use?

A: Use Top Hat's response system to engage students via their cell phones. No Clickers Required.

Top Hat: Student Response and Engagement System

https://tophat.com/features

• Students can text their answers if they don't have smart phones.
• professor and 30 students are free.

Please read more here