We have finished the journey of the wall functionality; congratulations!

In this chapter we saw how to use external web services, such as Akismet, to further extend the possibilities of our system; in our case, creating a custom validator that uses the Akismet service to validate comments and determine if they are spam or not.

In the next chapter we will jump to adding external content to our website using RSS feeds and we will learn how to integrate them and also how to cache the requests.