I have updated the Stock Quotes web part to fix the problem where the web part appears but without any visible quotes. Apparently in the last few days, Yahoo changed their code so that the CSV file returned is line delimited with a line feed (LF) instead of a carriage-return and line feed (CRLF). As a result, my code was incorrectly parsing the file.
The updated version of the file is available from the main article, or via direct download here.
If you have modified your own copy of the code, just edit this line in the RenderStockQuotes function:
Dim quotes() As String = Split(stockData, vbCRLF)
Dim quotes() As String = Split(stockData, Chr(10))