How do you keep Guestbook?

[Marketa0]

So I am sure that many of you are required to keep the Guestbook. We (in Czech republic) have to report to the city once per month and once per 3 days to foreign policy. The easiest way it to keep it online -  just send your guest a link for example with google doc that will tranfer into excel for us. However I am wondering if there are alternatives for google docs. Too bad airbnb is not doing anything about local law duties :,( Thank you