I was wondering on popular URL aliasing feature in drupal (to make urls more search engine friendly) is done by redirect. if yes will it become cause of penalty....?
No penalty and the redirects will happen internally in the web server so it won't actually redirect the client...
that was a great learning..i found similar post here http://www.webmasterworld.com/apache/3524863.htm
htaccess rewrites are a really cool thing to read up on. I remember when I first started learning them and I realised the possibilities. Might also be worth brushing up on your regular expressions also!
it is like permalinks in wordpress. all of these redirection is done without the 301 http code. the spiders don't see the redirection. for them it is just a html page.
I agree, what happens is basically the code looks at the url and sets the page to display the content. That would be the same as if you said: <?php if ($something = $somethingelse) { echo 1; } else { echo 2; } ?> PHP: The user only sees the echo.