I would choose just one application with three different profiles. Would opt for a presentation layer, a layer with the domain model or business layer and a data layer. The presentation layer would then be a web application, the business layer would contain all the logic and finally the data layer that abstracts the business layer operations with the database. The business layer in my opinion should be modeled using the domain language. Do you already create your data model?

Do you have any restriction on the technology to be used?

Have you read this code project article? How to Read and Write ODF/ODS Files (OpenDocument Spreadsheets)[^]

Why is it necessary to separate the data layer from the business layer? Are you thinking of changing the data repository? Is there another reason?

Strictly from a performance point of view, one assembly is always better than several assemblies. Each assembly loading has a fixed overhead. For multiple assemblies, you pay the overhead several times. The overhead of assembly loading at minimum includes the following: 1. Finding the assembly. 2. Loader in memory data structure tracking this assembly. 3. Assembly initialization. Possibly could be a problem of cold start. From a design point of view, duplicate code is a bad choice.

A software project ?

How are the site loading the images? Did you see that code? It is very strange that the image does not have the same size.

your post is not clear, please add details to your message.

Research for some sms providers, that give you a web service interface. It is the most practical/easy way.

Take a look at the Task Scheduler API: http://msdn.microsoft.com/en-us/library/aa383614.aspx

Check this article: http://support.microsoft.com/kb/312346[^]