Any table with name starting with '#' is automatically put 
into tempdb database.
Temp tables allow developers to create and scan tables 
within a stored procedure - and
have the tables totally isolated from all other database 
connections. This is very
valuable when results need to be processed several times 
within a loop, or when
a complex result set is expected (like a crosstab). Note 
that temp table transactions
are logged within tempdb (exception: select into create 
statements).

temp table is a temporary table,any user can use this 
temptable,it is one of the required database

Hi, This answer is with respect Sybase ASE database

# temp-table

A temp table is created with a prefix of #. These are 
session specific. That means if user-1 creates some temp 
tables with #<some name> and logs out and then logs-in into 
the database, he will not be able to see the #<table> which 
he created.

Shareable temp-table

In turn, if the user creates tables in tempdb without 
any "#" , then the table becomes shareable temp table. 
These will remain in tempdb till the ASE is rebooted. If 
the user logs-out and then logs-in , even in second 
sessioin he can still access these table.

- Pavan