What is the importance of good grammar? Well, if you are an English teacher it is probably very important to you. If you are doing an online job interview, it is important. But, if you are speaking specifically about online marketing, there are a few things to keep in mind. The author may be using English as a second language. What is the main reason that people are using a particular program? If the reason is to make $ and the program is working, most people won't care about the grammar or the spelling. Sure it will bother some, but I do not believe most people will quit a particular program that they find beneficial to them.