Before adding features, components, or different applications to your website, regardless if they are free or not, first you need to take a step back and decide on the primary goals of your website. You need to establish the primary purpose of the website so that resources are spent wisely. Added features should be based on items that will provide a return on investment, not on popularity or because it's the latest thing.
Of course if the latest thing is cool enough that it may give you added attention it's worth considering. Next, ask yourself, will your website act as only a marketing vehicle or is it meant to improve business efficiencies with elements like process application forms, orders, etc.?
Having defined the purpose of the site you can now create a list of required features.
For instance, if the purpose of the website is to sell your products online, you obviously will need to put your products online using shopping cart & e-commerce application.
Depending on how technical your products may be, you may also want to put online support documentation or instructions in a Knowledge Base or Forum with questions and answers. Some website features like the online Knowledge Base or videos are simply nice to have and may concurrently improve business efficiencies. However, they should all still support your primary goal. If you are a for-profit enterprise, Internet marketing is a must. SEO and PPC Advertising are just some of the Internet marketing solutions that generate sales or leads. Engaging in social networking through sites like Facebook, Twitter, LinkedIn, or any others, will again depend on your website's purpose or goals. Some sites lend themselves better to social media marketing than others.
For instance, a website that sells online tickets to major sporting events or concerts may see significant opportunity in using social networking sites to market their tickets. Most important to note is that adding a feature to your website but not using it, will do you more harm.
For instance, don't add a blog if you don’t plan on writing regular posts or a Forum if you're not going to moderate the questions and comments. It may not be easy to determine straightaway which features will provide a return or be of value to visitors.
In many instances the only way to really know is to either conduct a survey among current and/or potential users or to implement the feature and evaluate the web analytics to determine usage patterns. Listing your website's purpose and goals in priority will help you to decide on where to spend your resources. Having the appropriate features on your website that will enrich your visitors' experience can ultimately provide the highest return and lead to website success.