I don't know enough about Dropbox, but how well (performance wise) does it handle multiple readers/writers to the same folder/directory?  Over my years doing HPC, one of the biggest bottlenecks becomes the file system and the fact that huge parallel access (read or write) degrades performance immensely.

It is not easy: Dropbox will create different versions of a single file when there are more than one site are trying to modify this file.

The problem in some poor countries such Egypt that they can not purchase clustering progrms and other programs for high performance computing but may be they can develop programs that do the same jobs by shared folder and files on Domains or interenet

Basic problems: 

Atomicity

Consistency

Isolation

Durability

All of which can range from strong to weak. In database theory, strong is often assumed in all. They can be weakened, it depends on the application. For example, eventual consitency is often useful in many applications (e.g., naming services). Durability is often based on mission time. If you only want statistics, then isolation can be handled. In this case, you would have to check what your requirements are and how dropbox would meet them; there are several problems addressed in the previous answers.

Anyway, there are, as @Lauris Cikovskis mentioned, open source software for sharing information/processing so I would not go with PCs and dropbox and build something on top. Rather, I would develop my requirements and see which open source software package that meet the requirements and use that. If, and only if, no such open source exists or your requirements cannot be renegotiated to meet existing packages, then I would build my own.

I have, together with my colleagues, built a prototype DeeDS (Distributed Active Real-time database system) and (i) it takes a lot of time (not to forget verification and validation) and (ii) the theory behind such services are, at best, complicated and takes a long time to adopt. The prototype is not available, because similar open source solutions exists and we judged it to expensive to maintain (e.g., we adopted the OBST object store that, at the time, seemed to be a good idea, but later support for it was dropped). Therefore, I always advocate (re)use in this case.

Hi

Dropbox is really interesting to share some data, you can also do it with google drive, box, hubic ... But in all cases, you'll have a huge latency, and the data access will raise down the performances of your application. 

Why do you not manage and install your own dropbox like service ? You will have the control the infrastructure, and if you hosts the server, it will not have an impact, or a small one, on your performances.

You can find many solution, Seafile http://seafile.com is a really interesting solution, the server is developed for several platforms, and you have an api for many language ! You can manage the sharing options (local copy, read access only ...)

Best regards

Olivier 

I see nothing wrong with using dropbox for this.  But you should be aware that dropbox is not a charity: they'll only let you use services free for quite low levels of activity.  As others have mentioned, there are a variety of other free providers that you might leverage.  Of course, that means you'll find yourself wasting time managing a "farm" of free file stores, rather than getting work done.

I sympathize with the need to get by with low budgets, but I'm not sure you've thought carefully about how cheaply you can do network-storage yourself.  After all, the main value of dropbox is the syncing and platform coverage - if all you want to do is shift files over the internet, dropbox may not be idea.  For instance, there are many, many website-hosting sites that provide unlimited storage and bandwidth.  You may actually find it much more convenient to use https to get and put files - you may even find that some of your information is best stored in a DB (again, cheap hosting often provides preconfigured SQL access.)

Use the api acces to manage your file as you want, but like other, I don't think that the performance is the an important criteria of this service. 

After redaing the dropbox api, it is very simple (maybe too simple), show the other similar api to compare and find the must in adequation with your usage (keeping in your mind that the performance are not challenged for this service).

Show maybe the c2 amazon service to use all your worker in the "same"   provider.