What is spam ?

Spam is text or URL, in one or several exemplars, neither being waited nor wished, not having, neither directly nor from its shipper, no relationship neither with the recipient nor with a possible
resource related to the recipient.

How does spam appears in blogs ?

• Through the comments body and commentators URL.
• Through trackbacks excerpt and permalinks URL

What are the anti-spam methods?

• Authentication by connection
• CAPTCHA
• Black List
• Bayesian Filter

Other methods to minimize spam :

• Time Interval between submissions / Number of submissions per hour.
• DDD.
• Secure Form Mode : force page and submission to be manual.
• Rank Denial : Directs hyperlinks an intermediary server.
• Autoclose after N days: entry stops accepting comments or trackbacks.

Which data are analyzed by these methods ?

Active methods do analyze the shipper to check if its:
• a spamer by coparing its IP address with blacklisted ones.
• authorized by authentication
• a human by CAPTCHA

Passive methods do analyze :
• comments data:
  • nickname
  • eMail address
  • URL
  • message
• trackbacks data (concerning the shipping blog):
  • blogs name
  • entrys title
  • entrys excerpt
  • permalinks URL

What are the limits to these methods ?

Cross use of several of these methods allows excellent results concerning comments, but weak results concerning trackbakcs.
Difference between comments and trackbacks is that comments are sent from the recipients blog, which allosw all above methods to be used, whereas trackbacks are sent from the shipping blog (this avoids the use and need of 2 interfaces).
- Consequently its not possible to use CAPTCHA, authentication and Secure Form Mode methods with trackbacks.
- Another big problem, when all the trackbacks data are unknown, especially the IP address, it is quite impossible to avoid spam, mainly because the blacklist and the bayesian filter are becoming inefficient.
- Last inconvenient, trackback autodiscovery is usefull for bookmarklets but also to spamers to who it gives the trackback URL.

Glimpse on futures anti-trackback-spam methods