I do a daily e-mail. I send it during nap-time.
It includes what was served at morning snack & lunch and what will be served at afternoon snack. I also include how many bowel movements (bm's) and a recap of what we did that day. It is also how I notify parents if I need diapers & wipes or a change of clothes for their bin.
For any other issues, I send those in a separate e-mail - like upcoming vacation days, appointments etc. I find if they don't have their own e-mail with a dedicated subject line, information can get missed.
I also send pictures via e-mail - I upload them to an online album & the parents can view them and share them with their families.
Everyone likes the daily e-mail and I find it so easy to communicate with everyone.
I also text with parents for more child specific stuff.