2. As our website grows, so does grows the spam attack on it. There
are several well-known methods to prevent the spams. Here I
have reviewed 4 of the most commonly used drupal modules to
protect spam:
1. Captcha
2. Hidden Captcha
3. Spamicide
4. Mollom
3. CAPTCHA is the oldest and most widely used spam filter. It
presents with audio/visual challenge to the user which they must
solve inorder to prove that they are human. But the smartest
bots are smart enough to solve these challenges as well.
However, we can prevent bots by increasing the difficulty or
amount of distortion in the captcha.
4. I have seen sites presenting with most difficult captchas which I
am never able to get through in first few attempts, I end
up believing that I am a bot!
Difficult captchas do prevent spams but this of course comes at
the cost of punishing our faithful users with difficult challenges
which may refrain participation.
5. HIDDEN CAPTCHA is a user friendly solution and this is
the thing I like about it – it does not require my users to prove
that they are human and while they are being screened they
don’t even get to know that their post is being tested.
It doesn’t test whether the poster is a human rather it tests
whether the poster is a bot and then restricts posting by bots.
This module creates hidden fields which are not visible to human
posters but bots tend to fill in each and every field.
The moment bots fill in fields not visible to human posters,
hidden captcha classifies it as spam and doesn’t allow it to be
posted.
6. One reason why I wont be using Hidden Captcha is that with little
experience the bots learn to skip the fields meant to catch them.
To outsmart the bots I’ll have to regularly and smartly keep
changing the questions so that I can fool the bots every time.
This filter is of course easy and user friendly but the time factor
involved in keeping the filter robust is something we all are not
ready to compromise in our busy schedule, we want something
that is that is robust and easy for us as well as our users.
7. SPAMICIDE is very much similar to hidden captcha. This
module also creates hidden fields not visible to human posters.
Both hidden captcha and spamicide are well maintained and
popular, but hidden captcha depends on the CAPTCHA module
while spamicide is standalone. CAPTCHA can count the number
of times it misses whereas Spamicide doesn’t count.
Spamicide auto-injects itself in all forms which is kind of a waste
for all the Admin forms.
I will always prefer spamicide over the first 2 modules discussed
here because it is easy to use, easy to set-up and it filters out
most of the spam.
8. Mollom is like a human moderator on autopilot and it is often
referred to as “intelligent” web service.
The way mollom function is, by splitting the content into 2
categories: ham or spam. Ham is the desirable content posted by
us “the human being” whereas spam is the undesirable content
posted by the bots that needs to be filtered out.
9. All the incoming content undergoes mollom screening and gets
published on the website only if it falls under the “ham” category.
Mollom keeps updating its deciding factors by analyzing the
history of activities within its network.
It also considers the content of the post and poster’s reputation
while determining whether to post the content or not. Whenever
Mollom is unsure, it performs second level check – by presenting
to the poster an audio or visual CAPTCHA challenge that they
must complete in-order to post the content.
I have found Mollom as one of the most robust filter for spam
which keeps getting intelligent. Atleast one filter that gets
intelligent as the bots are getting intelligent.
10. Captcha Hidden Spamicide Mollom
Captha
Method of Spam Challenge response Hidden input Hidden input Filters out spam
Detection test field field based on
intelligent
content
moderation
User friendly No Yes Yes Somewhat
spam filtration
process
User interaction Required Not Not Required Seldom
Required Requried
Dependency on None Depends on None None
other module Captcha
Module
11. Captcha Hidden Captha Spamicide Mollom
Pros Easy to setup and Identifies bot Does not Believed to block
blocks nearly all activity when hidden interfere with 99.93% of spam
spam. It comes with a fields are filled. No the user and offers two
few different styles interference with experience in SPAM prevention
and is quite user experience. anyway. techniques. The
configurable traditional
CAPTCHA test,
and an invisible
word filter.
Cons Not user friendly. It doesn’t block as Spamicide auto- The filter can
Advanced spam bots much spam and you injects itself in all sometimes flag
can understand the need to change the forms which is legitimate entries
captcha and get question every so kind of a waste as spam. Users still
through. It takes up often once spammers for all the Admin have to read and
space on the page start to catch on. forms. type in the
and adds visual About once or twice captcha.
clutter. a month.
12. Of the 4 modules, Mollom is the most effective spam filter and it
is growing on its intelligence to use it for spam monitoring.
However, this is also not a 100% cure for spams. But using
Mollom with Spamicide is an effective shield for your Drupal
website against spams which in most cases filter out 99.99% of
the spams.
