The phrase "old post" refers to something that has been previously written or said a while ago, usually on the internet. It suggests that the information or discussion is not recent or up to date. Full definition
Case in point... My product content came from a series of old posts on generating online income. (stevescottsite.com)
I spent some time looking at older posts on your blog and realized that I would like to come back and visit. (goodbyehousehellohome.com)
The store itself is a beautiful old post office building which has been converted into a colorful and vibrant gluten - free cafe and grocery shop. (glutenfreedoll.com)