It has become mandatory to use Facebook and Twitter as part of your website marketing strategy. The development environment for both Facebook and Twitter is finally getting to a point to allow good integration among the various platforms.
This can be a formidable task for the developer/consultant as well as the client to understand how the platforms all tie into a marketing strategy.
Except for large project, we develop exclusively on WordPress for websites, and fortunately there are some great plugins to easily (almost) set up a way to PUSH or PULL content between your website and FaceBook Page and Twitter account. The client may want to post their content on all platforms separately, but this is burdensome for most. It is more likely they will want to post on one platform primarily and have it disseminate to the others automatically.
The first question is to ask where the client feels most comfortable publishing content. If the spend their day on Facebook, then the solution is better to pull content from Facebook to the website. A good plugin for this is Facebook Like Box. This will add a like button, photo gallery and the posts as a widget.
To pull tweets I depend on Genesis – Latest Tweets. We develop all our sites on the Genesis Framework and this is one of many great plugins included.
If the client wants to publish on their website, they will want to PUSH their data to both FB and Twitter. I recommend WP-To-Twitter and Facebook-page-publish for these tasks (also Wordbooker). To accomplish both of these tasks, you will need to establish an application.