Web Parts were introduced in SharePoint as part of Windows SharePoint Services 2.0 / SharePoint 2003. They are not solely unique to SharePoint, they are in fact a feature of the ASP.NET Framework, the development platform that SharePoint is built on. As SharePoint was built on top of ASP.NET, SharePoint leveraged this feature.
The definition according to the original TechNet article in 2005 is:
“ A Web Part is a Microsoft ASP.NET server control that serves a particular purpose, such as displaying data from a spreadsheet or streaming stock quotations from an online Web service.“
End users will more likely recognize the following definition:
“A Web Part is a widget, which can be placed on a page and supports a distinct element of functionality, like displaying new headlines or cycling through a set of photos.”
A Web Part is an immensely powerful means to build up the content and functionality of a SharePoint page. Each Web Part implements a specific feature, and combined with other Web Parts and content, they can form any type of content page.
Web Parts are placed in so called Web Part zones. In SharePoint 2010, it also became possible to add Web Parts directly into the content, typically in wiki pages. Technically speaking, the Web Part was still added to a hidden Web Part zone, but from a user’s point of view, he or she was adding Web Parts to the page content directly - which made the whole process much simpler for users.
Why Are They so Useful?
What is missing from the earlier definitions though, is that Web Parts are reusable. They can be added to multiple pages to replicate the same functionality. By configuring its specific options, there's enough flexibility to fulfil the specific requirements of each page - meaning one solution tailored to slightly different needs.
For example, aggregation of pages in SharePoint is a quite common use case - often users will want a landing page showing all subpages, a sort of dynamic menu. The Content By Query Web Part is perfect in this scenario, as it offers a lot of configuration options, e.g. for the filter, data source, display templates, sorting, etc.
This means it can be used on one page to show results in a certain way, and the same Web Part on another to show a totally different cut (and format) of content.
What Web Parts Are Currently Available in SharePoint?
SharePoint comes with a lot of Web Parts out-of-the-box. Which ones are available depends on your license, exact version, and which features you have activated on your Site Collection.
This overview by Laura Rogers is an excellent summary of all available Web Parts, but the really interesting ones are:
Contact details - Add a contact card or short person bio to a page, with the information pulled from the standard SharePoint user list.
Search - There are a number of Search Web Parts, which used in different ways means you can replicate search and search results in any part of your site.
Picture library - Display a slideshow of photos
Media Web Part - Embed videos right on the page
Other popular Web Parts for modern dynamic SharePoint systems are the Content Search Web Part and the Content By Query Web Part. These Web Parts are highly customizable and allow to aggregate content across your SharePoint environment.
The Content By Query Web Part has the advantage that the results are real-time, contrary to the Content Search Web Part that depends on the SharePoint indexing to happen. However, the Content By Query Web Part is limited to one Site Collection only, where the Content Search Web Part can display data that exists in multiple site collections.
Web Parts Add Something Extra to SharePoint
So quite simply, a Web Part is a part of a page. Combined with text and images, Web Parts form a web page.
A Web Part may leverage SharePoint features to make the experience even better. For example, with audience targeting, the display of the Web Part will differ from person to person, based on his role, location, or function. This allows for Web Parts that display location specific news articles, to only be visible to those users who actually work at that location.
This really uses the power of SharePoint, and makes it the flexible content and Intranet tool it has become today. Office 365 new Web Parts, or App Parts as they have been renamed, are offering even greater levels of flexibility and customization.
Web Parts Are Awesome
Sure, in theory everything you can do with Web Parts, can be achieved by just creating static content. A news overview on a homepage? Sure, just add a static list of items to the homepage and you’re done.
But what if you want this list to update dynamically when you add a new article? Look no further than Web Part! They’ll make your life easier and will do certain features, such as aggregation, automatically for you.
Want to display the latest stock information? Use a Web Part! Want to add a list overview to the homepage? Use another Web Part!
Web Parts, along with Lists, are one of the fundamental aspects of SharePoint content management. Beneath all of the advanced features that have joined SharePoint over the years, Web Parts are still proving invaluable and when used smartly and can make your SharePoint experience even stronger.