Newsletter: Newsletter is a great way to keep your audience glued on to all that is happening on your blog. It is best way to know who your loyal audience is.
Recommend content is advisable for E-commerce bloggers. For e.g. Recommended books. A buyer will want to know what more is there in store for him/her.
E-commerce bloggers can gradually choose to write curated content from other websites/blogs. That always helps because a buyer will generally not spend much time surfing. He/she will appreciate it if you provide most of what they are looking for.