Preethiviraj Kulasingham

1.  "Instead of triggers overright your update statement and you can't refer blob columns.  That means you have no mechanism of updating the blob column through instead of triggers."

This is a bit misleading.  The subject of the article is auditing via triggers, not updating the same table's blobs via triggers.   Blob fields are accessible for "INSTEAD OF" auditing in the Inserted and Deleted tables. 

See BOL:

"SQL Server 2000 does not allow text, ntext, or image column references in the inserted and deleted tables for AFTER triggers; however, these column references are allowed for INSTEAD OF triggers."

2.  This is interesting.  Although it is true that UPDATETEXT/WRITETEXT (and potentially bulk copies) are not logged and do not fire triggers, these functions are not commonly used.  Most blob updates are performed through regular Update statements that are logged and fire triggers.   However, when UPDATETEXT/WRITETEXT statements are used, it is simple enough to manually update the audit table, e.g. in the same SP.  I don't think this is a reason to reject the technique.  It's just an unusual application-specific quirk that we may need to take into account when writing audit procedures.