I would bet it will be google charts, which would be a shame. They 'renew' its existence every year and have said they will give a year warning. I am currently

I would bet it will be google charts, which would be a shame. They 'renew' its existence every year and have said they will give a year warning. I am currently building a site with it but will start looking into a backup for migration, if things go well. The only reason it might survive is that google still uses it for google finance.