google chart deprecation policy mean

maybe my English is not good. but what does the deprecation policy mean on google chart term mean?

http://ift.tt/19Jl7j3

it is said that "After April 20, 2015, this Deprecation Policy will not apply."

what happened after 20 April 2015? can i still use it after 20 April 2015? is it wise to use it for long term?or Google could just wipe the API anytime?

another question, can i use it commercially? thank you very much before