please explain spider.txt

Can someone explain the spider.txt file please? I see it in the includes folder and its loaded with over 396 entries including googlebot, yahoo, Microsoft and other common search engines.

From what I can tell spider.txt is used to block these bots, right? Well I can understanding wanting to block malicious bots, but I want the search engines to index my site. If I have these popular search engines in spider.txt does that mean my site wont get indexed?

What’s the best way to protect my site, but still allow it to be indexed by the search engines?

Thanks
:huh:

The spiders.txt file is used to identify bots when they visit the site, so that the site knows that they're bots and lets them do the indexing that's needed.
It is not used to block them from indexing your site. It only blocks their ability to place purchases on your site ... since that would confuse things significantly.

ahh, ok. That makes me feel better.

I recently noticed a logged in "guest" entry in "Whos Online" with credentials referencing a host of searchme.com and with charlotte in its useragent line. Scrutinizing spiders.txt revealed no entry for searchme or charlotte (searchme's spider).

by comparison, I noticed that yahoo had a spiders.txt reference of:
"yahoo! slurp"
...as well as an apparent entry of just:
"slurp"

Would someone outline the procedure for correctly identifying and adding a new spider to spiders.txt?

Should one add "charlotte" to spiders.txt, or "searchme charlotte", or both?

Or is there someplace on line that publishes an up-to-date list of all current known spiders?

(I wish i'd have copied the searchme's Host and User Agent entry as it was seen in admin ...but they're no longer online.)

Thanks for any feedback...

Ah, it's back ...here's the sample:

Host: crawl1.nat.svl.searchme.com
User Agent: Mozilla/5.0 (compatible; Charlotte/1.1; http://www.searchme.com/support/)

I added "charlotte" to my spiders list and zc admin now identifies them as such ...and no session! However, without trial and errror, my questions above still stand:

1. Would someone outline the procedure for correctly identifying and adding a new spider to spiders.txt and how to know what text to include?

2. is there someplace online that publishes an up-to-date list of all current known spiders?

This post helped tremendously, I had originally set 'Force Cookie Use' under 'sessions' to true after I tested adding to cart from a different computer and ran into the warning that cookies must be enabled (they already were on that computer). I set it to false again and used the updated spiders.txt file Dr. Byte provided, looks to be working now, much preferable this way. Thanks!