We received an interesting comment in the site the other day about the anti-spam options that we incorporate into the Issue Tracker component. The main gist was that Recaptcha was the only anti-spam option that we use. However we had to reply that there were also other features such as word filtering, IP blocking, checks on the number of links, and the ability to ban specified email addresses and URLs.
We have (and still are) considering other options but do wonder whether it is the best approach to build all of these tools into a specific product such as Issue Tracker. A typical Joomla site will have a number of components such as a Blog, a forum, a general article commenting system, etc., installed. Other web sites even if not based on Joomla will have similar constituents. Is it wise to have all of these parts with their own separate anti-spam measures? The likelihood is that they will all adopt slightly different approaches with different measures of success, and all requiring updates to keep up with new techniques and methods.