LOBs Vs BLOBs Vs CLOBs

- LOB (Large OBject) refers to any of these types, It's either BLOB or CLOCB .Which have a special way of being stored internally, on special pages called 'LOB Pages'.

- BLOB means Binary Large OBject and only refers to image.

- CLOB means Character Large OBject and refers to text or ntext.

A column of LOB data can store up to 2GB worth of data, so that could be lots of pages. 

P.S : Next version of SQL Server 2012 and 2014 , Microsoft will be discontinued the data type ntext and text. This both the data types replacing with varchar(max) and nvarchar(max)  which will support the existing data type and you can convert existing records also.