You can show wall posts of any public facebook page/group/profile
using Graph api in your website if you know javascript & jquery.

Asp.net makes it easy to export tabular data to excel file.It's
easier to use GridView control data to export to excel.the following
codes shows how u can achieve this along with some header info at the
top of the data rows in excel -

It's a good idea to identify the errors at run time to detect
and handle it. .Net framework has built in mechanism for that.
these exceptions occurs because of user,logic and system errors.

A CAPTCHA is a program which tells whether its user
is human or computers.

follow the steps below to add captcha in your web form
easily -

verbatim string is a string which is interpreted
by the compiler exactly as it is written, meaning
that even if the string spans multiple lines
or keeps escape characters,etc.

Facebook access token is needed whenever you access
facebook stream of page or profile, Graph api call to post
to facebook.there are many ways by which you can generate
access token.By the following way you can create short lived
access token for a user as well as extend it to long lived
token -

The abstract class indicates that a class may be used
as a base class for other classes and is not instantiable.