Looking on the internet deeply has found these results:

I am following up on your email is the most popular phrase on the web.

I am following up to your email 11 results on the web	I am following up on your email 15,660 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
No sir, I am following my orders. But here I am following him again. I'm following up on my email. I am following up these issues with Committee of European Securities Regulators (CESR) and I intend raising them also with our international partners. I am following up on a lead on corruption at the DWP. This time I confess I am following you. But I am following up on the fiancee. I am following up on my story about crime in Central City.	I'm following up on my email. I am happy to inform you in this context that last June the Commission revised the mandates of its heads of delegation, following up on the report by Mr Agnoletto. I am way too busy planning and organizing and following up on things to actually think about socializing. I am following up on a lead on corruption at the DWP. But I am following up on the fiancee. I am following up these issues with Committee of European Securities Regulators (CESR) and I intend raising them also with our international partners. This time I confess I am following you. I am following up on my story about crime in Central City.

I am following up to your email

11 results on the web

I am following up on your email

15,660 results on the web

More popular!

No sir, I am following my orders.
But here I am following him again.
I'm following up on my email.
I am following up these issues with Committee of European Securities Regulators (CESR) and I intend raising them also with our international partners.
I am following up on a lead on corruption at the DWP.
This time I confess I am following you.
But I am following up on the fiancee.
I am following up on my story about crime in Central City.

I'm following up on my email.
I am happy to inform you in this context that last June the Commission revised the mandates of its heads of delegation, following up on the report by Mr Agnoletto.
I am way too busy planning and organizing and following up on things to actually think about socializing.
I am following up on a lead on corruption at the DWP.
But I am following up on the fiancee.
I am following up these issues with Committee of European Securities Regulators (CESR) and I intend raising them also with our international partners.
This time I confess I am following you.
I am following up on my story about crime in Central City.