out of curiosity, and probably topic, the 70chars limit is probably due to the protocol, but, is there a way to post longer messages? or what do people do to "certify" longer messages on the blockchain? I heard pitches where companies told that they were securing contracts and so on (not sure if they just post the hash or what).

PS: Does anyone of you know what kind of API/implementation this site use to post the message on the blockchain? i'm new to the topic but quite interested