Tracking Clickthroughs - Anti Bot Techniques?

I need to track clickthroughs from my clients site, but what about BOTS?!

[netnerd]

I am setting up some sites that will be paying me revenue based on the number of click throughs they generate.

I need
a) A way to keep a count of how many clicks through each separate link

and

b) A way to ensure i dont 'double charge' for people multi clicking a link (I guess i can get round this with IPs) and more importantly,

how do i ensure i dont count bots spidering the site as click throughs?!

Hope someone can help me with advice or a script!

[cfx211]

Most good bots identify themselves in the user agent field in your logs. I would find a list of bot user agents and then filter those out when counting up referrals in your logs.

For us, we exclude the following when counting up visits to our site, but this might not be completely up to date so do a search for a site that regularly maintains a bot UA list.

where user_agent not in ('Googlebot/2.1 (+http://www.googlebot.com/bot.html)',
'ia_archiver',
'Mozilla/2.0 (compatible; Ask Jeeves/Teoma)',
'TurnitinBot/1.5 [turnitin.com...]
'Mozilla/5.0 (Slurp/cat; [e-mail]; [inktomi.com...]
'FAST-WebCrawler/3.7/FirstPage (atw-crawler at fast dot no;http://fast.no/support/crawler.asp)',
'Mozilla/3.0 (compatible)',
'FAST-WebCrawler/3.6 (atw-crawler at fast dot no; [fast.no...]
'Teleport Pro/1.29',
'Mercator-2.0',
'sitecheck.internetseer.com (For more info see: [sitecheck.internetseer.com)',...]
'Mozilla/3.0 (compatible; Indy Library)',
'larbin_2.6.2 [e-mail]',
'Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt; DTS Agent',
'KMcrawler',
'FAST-WebCrawler/3.7 (atw-crawler at fast dot no; [fast.no...]
'Mozilla/3.0 (Slurp/si; [e-mail]; [inktomi.com...]
'libwww-perl/5.64',
'Mozilla/2.0 (compatible; T-H-U-N-D-E-R-S-T-O-N-E)',
'Googlebot-Image/1.0 (+http://www.googlebot.com/bot.html)',
'Libby_1.1/libwww-perl/5.65',
'Lynx/2.8.4rel.1 libwww-FM/2.14 SSL-MM/1.4.1 OpenSSL/0.9.6b',
'http://www.almaden.ibm.com/cs/crawler [c01]',
'http://www.almaden.ibm.com/cs/crawler [wf55]')