What are expired points?

Please explain this concept to me. Thanks.

Points that you earn from being active (saving and learning a lot of LingQs) expire after some time (90 days I think).

I don’t know about points from tutoring and/or uploading content which other members download for their use, though.

All points expire after 90 days. Take a look at these FAQs on points, http://www.lingq.com/help/en/points/