Steps to prevent spam on system like Digg

Question

Heya guys, im currently working on a system that's based around the concept of Digg where as you have a button on an external site and a user who clicks that button gets to post / digg it.

Anyways, Im looking for some information on the types of spam that I will expect as time grows on.

So far I have thought about a fair few factors, such as flag system, X rates by different users before frontage, Domain Monitoring, and some others..

Any ideas on what money hungry site owners would try and attempt ?

Thanks in advanced Robert.

Answer 1

I expect creating a system like digg's, you will be prone to problems like:

• Voting from bots to get items higher (prevent with captcha, time delay between vote ups, karma system)
• Organised groups of users voting eachothers stuff up (to combat this you can try comparing submissions with votes from other users. If User A always votes User B's content up, and vice versa, you have a fixed result)

Plus the more common problems - mass account creations, mass automated submissions, spam being added. These are combatted using the systems you have mentioned, plus a bayesian spam filter.

Answer 2

Instead of telling you what you should watch out for, here's a more proactive approach: take a look at Akismet, CAPTCHA, DNSBL checks, and bandwidth throttling. All these can be done in PHP. This way you can start real-coding and not vapor-coding.