I am new to the business field. I usually depend on the internet and social media to promote my business. But I don't think that's enough to reach the potential customers. Rather than internet marketing we have decided to keep our focus on some other platforms to promote our special offers, sales and seasonal products and other opportunities. I think the strategies like direct mail services can help to grab the attention of targeted customers. Currently, we have decided to concentrate on promoting business via postcard printing services. How effective do you think postcard can be to promote a business? What is the standard size of postcards?