QUOTED_IDENTIFIER ON and ANSI_NULL ON?

If we create a Stored Procedure in Query Analyzer/ Management Studio, it is created with following SQL commands prefixed.
What are these – QUOTED_IDENTIFIER ON and ANSI_NULL ON?
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

Answer from Tulika:

SET ANSI_NULLS
When SET ANSI_NULLS is ON, a SELECT statement that uses WHERE column_name = NULL returns zero rows even if there are null values in column_name. A SELECT statement that uses WHERE column_name <> NULL returns zero rows even if there are nonnull values in column_name.
When SET ANSI_NULLS is OFF, the Equals (=) and Not Equal To (<>) comparison operators do not follow the ISO standard. A SELECT statement that uses WHERE column_name = NULL returns the rows that have null values in column_name. A SELECT statement that uses WHERE column_name <> NULL returns the rows that have nonnull values in the column. Also, a SELECT statement that uses WHERE column_name <> XYZ_value returns all rows that are not XYZ_value and that are not NULL.
When SET ANSI_NULLS is ON, all comparisons against a null value evaluate to UNKNOWN. When SET ANSI_NULLS is OFF, comparisons of all data against a null value evaluate to TRUE if the data value is NULL.


Example:
set ansi_nulls on declare @myTab table (id int null, [name] varchar(10) null)
insert into @myTab (id,[name]) values (2, 'dave')
insert into @myTab (id,[name]) values (3, null)
select * from @myTab
select * from @myTab where [name] is null
select * from @myTab where [name] = null


SET QUOTED_IDENTIFIER
When SET QUOTED_IDENTIFIER is ON, identifiers can be delimited by double quotation marks, and literals must be delimited by single quotation marks. When SET QUOTED_IDENTIFIER is OFF, identifiers cannot be quoted and must follow all Transact-SQL rules for identifiers.
SET QUOTED_IDENTIFIER must be ON when you are creating or changing indexes on computed columns or indexed views. If SET QUOTED_IDENTIFIER is OFF, CREATE, UPDATE, INSERT, and DELETE statements on tables with indexes on computed columns or indexed views will fail. For more information about required SET option settings with indexed views and indexes on computed columns
When a table is created, the QUOTED IDENTIFIER option is always stored as ON in the table's metadata even if the option is set to OFF when the table is created.

Example:
SET QUOTED_IDENTIFIER OFF
GO
-- An attempt to create a table with a reserved keyword as a name
-- should fail.
CREATE TABLE "select" ("identity" INT IDENTITY NOT NULL, "order" INT NOT NULL);
GO
SET QUOTED_IDENTIFIER ON;
GO
-- Will succeed.
CREATE TABLE "select" ("identity" INT IDENTITY NOT NULL, "order" INT NOT NULL);
GO