Running a blog and related applications, is nowhere near the most taxing thing you can do to your server in Vietnam.
The reason why blogs can cause problems is that, in addition to running PHP, they make a lot of queries to a database. They pull the post, the author, the comments, the images and almost every element from the database. Shopping carts have that same issue many times over. Descriptions, sizes, prices, images, titles, sales, reviews, comments and every little element is stored in a database and must be called on every page load. A moderately busy shopping cart can be worse than a very busy blog. Shopping carts, especially older ones, can be very taxing and should be used with caution. Though a shared hosting account can withstand the load of a small store, as traffic grows you may find yourself having to move up sooner than expected to keep speed and stability high.
Solutions: Make sure you are using a modern shopping cart, such as Zen Cart, rather than OSCommerce, which it is based upon. The newer carts are more streamlined and easier to use. Other systems, such as Store Sprite, are also leaner than their ancestors.
Streaming audio or video may not fry a server VN in the way that thousands of users pounding a database can, but there is no doubt that they can bring it to a crawl.
Hosting large media files on your server is a strange form of suicide. As more and more people access your media directly, it takes away bandwidth and resources from actually serving your site. Summary, the “tubes” leading to and from your server can easily get so clogged with people trying access your media that they cannot reach your pages or cause them to load slowly. Worse still, if you have a bandwidth cap, there is a realistic chance you will go over it.
Streaming media from a shared hosting account is asking for trouble. It is better to avoid it altogether.
Solutions: Use a CDN to host your static files. They are faster and, in the long run, usually cheaper. If that fails, find a good media host like YouTube, both of which are free.
While it is true that a blog can be difficult on your Vietnam server just about any application has the potential to under high load. However, some apps are far more demanding than others and you need to be aware of how taxing something is before buying your hosting so you know how much power to get.
That being said, it is very easy, especially for a newcomer, to not understand how taxing their intended use might be and make mistakes. This can lead to a very poor hosting experience, often one that the host gets blamed for.
Be aware of what you are trying to do and plan accordingly. Otherwise, you may be responsible for burning down your host’s datacenter, which is not likely to lead to a lasting relationship.