Internal or external marketing?

Thanks Hoa Dang Ngoc and Andrew Dang for your valued experience sharing. I gree with you that In and External marketing are so important to every company. Howerver, I prefer Internal marketing firstly. I worked for some Co. Ltd before, they always had ONLY plan for external marketing to customers. Actually, many customers knew their products but their staffs did not have deep/united understand about their products. Even staffs did not believe, happy and confidence to sale their products.

In my opinion, any company have to do both of the internal and external marketing. Internal Marketing is the best practice for external marketing success. The success should come from inside out :D
Internal marketing motivates and empowers employees at all management levels to deliver a satisfying customer experience.

Interesting question, Trung! if your prefer your question to Vietnamese Family companies, then I think you already had an answer, which is neither Internal or External marketing especially "small and average company level". Right? :)
However, since you asked, here are my thoughts.

Consider this, companies that have highly evolved product and service development practices understand the importance of empathizing with customers, and that different customers respond to different messages. Thus, it is clear that we need different messages for different audiences, so that’s not the issue. The issue is how to create messages that are complimentary and compatible. It’s not about hiring a copywriter to craft a perfect compromise of a tag-line …. though you’ll need that too. This is where a good marketer cones in. How do marketers create external messages that are authentic, and appropriate, but which also consider and respect the culture of those we are engaging with?

In some ways, I wonder if it’s easiest to think of the externally facing messages as being more introductory, and the internal messages as being more meaningful and deep. When you meet someone new, you don’t start with the philosophy you bring to your work, you just introduce them to what you do and hopefully what makes you uniquely interesting. Ideally, what you start with foreshadows what is to come. In the end, I don’t see any downside to sharing the internal perspective once you’ve got a real relationship going. If that’s the case, then marketers can focus on opening those windows between silos, facilitating the articulation of the company identity, creating complimentary messages, and fostering alignment

So, as Hoa Dang Ngoc has indicated, for a successful launch of new products and services, both Internal and External marketing have to be done and executed in timely order, from inside out.

Uhm, did I answer your question? :)

both

NO INTERNAL, NO EXTERNAL: GUERRILLA MARKETING

To be frank, I may be a basic person but the existence of Marketing is to satisfy the client. Unless the client is our employees (which business model exist, like catalogs of products selling to teachers in the Ministry of Education -France-), Marketing can only be External with the unique target to get more clients.
Now small and medium companies should only do Guerrilla Marketing -read Jay Conrad Levinson bible for effective Marketing.

When you work for big companies you learn how to use best (and fast) a Marketing budget. The measurement of performance for 1$ invested how much you get is left to financial accounting and year end results (of course I am exagerating, but look at how many companies have a website that cost them time and effort from a marketer and It programmers and machines for ???$ sales?

Start measuring the results in profit -you need financial analytical skills- for each marketing action, then you will know exactly which "marketing weapon" to keep and which one to stop/cancel/terminate.