One weakness of Visual Basic derived languages such as
Visual Basic 6.0 and the VBScript scripting language commonly used to write ASP
scripts is that string concatenation is very inefficient. This inefficiency
can be magnified exponentially if concatenation is performed during a looping
operation, such as joining together records from an ADO RecordSet. The
inefficiency exists because every time a concatenation is performed a new
string object must be created in the memory. The inefficiencies of string
concatenation also affect the .NET Framework.